WO2004059829A1

WO2004059829A1 - Electric motor comprising an integrated electronic control device

Info

Publication number: WO2004059829A1
Application number: PCT/DK2003/000875
Authority: WO
Inventors: Poul Erik Nielsen; Per Østergaard NIELSEN; Bernd Pawlowski
Original assignee: Danfoss Drives A/S
Priority date: 2002-12-31
Filing date: 2003-12-15
Publication date: 2004-07-15
Also published as: AU2003287893A1; DE10261450A1; DE10261450B4

Abstract

The invention relates to a standard electric motor comprising an integrated electronic control device and a sensor which is connected to said control device by means of a safety device. The aim of the invention is to avoid the expenditure of energy by the user for establishing the connection between the sensor and the safety device. To this end, the sensor (51) is arranged inside the motor housing (126, 128) and is used alone or also as a safety sensor. Furthermore, the sensor is connected to an electronic safety device (4) arranged in another housing (127) applied to the motor housing, said safety device being connected in turn to the integrated control device (2).

Description

Electric motor with integrated electronic control device

The invention relates to an electric motor with an integrated electronic control device and a sensor connected to it.

In a known electric motor of this type (DE 10207834A1), the sensor is arranged outside the motor on its shaft in order to regulate the speed down via a safety device arranged outside the motor and the control device designed as a control device in the form of a converter. The wiring between the sensor and safety device must be carried out by the user.

It is also known to retrofit such a motor control device with a safety device for switching off the motor with a safe stop. This also requires complex wiring on the part of the user.

The invention has for its object to provide an electric motor of the type described, in which the amount of work and the costs are lower on soaps of the user.

According to the invention this object is achieved in that the sensor is arranged within a motor housing and serves alone or additionally as a safety sensor and is connected to an electronic safety device arranged in a further housing mounted on the motor housing and connected to the integrated control device.

With this solution, a completely finished system is delivered to the customer. A considerable amount of wiring on the part of the user is eliminated. The The electric motor is secured at the factory and adapted to the safety sensor. Additional parameterization between the sensor and the electric motor is therefore not necessary.

Furthermore, this solution is space-saving: if the sensor serves as a speed sensor, it usually has an axial length of 5 cm, so that the motor shaft has so far had to be extended by this amount. In contrast, when the sensor is installed in the motor housing, the size of the electric motor does not increase. Another advantage is that the wiring between the sensor and the control device can be kept short. The consequence of this is that a long, expensive safety cable is not required and the probability of errors, for example due to a disconnection of the cable, is significantly reduced.

The sensor is preferably a speed sensor and is attached to the motor shaft. With the so-called "safe technology", a speed sensor on the motor shaft is usually required. Although the speed can be derived from an internal physical quantity of the control device, this measurement would result in an error if the rotation was caused solely by an undesired rotation of the device driven by the motor.

The speed sensor can be a redundant sensor that consists of two independent speed meters. This helps to increase security.

The safety device is preferably mounted in the further housing on a first card and the control device on at least one second card. In the event of a component on a card being defective, it can easily be exchanged for an error-free one without the other cards having to be exchanged. However, it is also possible for the safety device and the control device to be applied in the further housing on a common card. This simplifies production.

It can then be ensured that the safety device has electrical connections which are accessible through a wall of the further housing and enable the connection of external signal lines, e.g. Signal lines of an emergency stop switch or a communication bus. In this way, a stop signal can be transmitted to the electric motor by other devices in order to achieve a "safe stop".

Conversely, it can be ensured that security feedback from the security device to external units, e.g. a programmable logic controller or an external safety device through which electrical connections are routed.

The safety device can have two microprocessors, which mutually monitor each other for errors and continuously check the functionality of safety switches and the input and output connections of the microprocessors. This test is therefore carried out automatically within the safety device without appearing externally.

In particular, the safety device can have the function "speed monitoring" and switch off the control device when a speed limit value is exceeded, so that the motor is also stopped.

The safety sensor can alternatively be a torque sensor or angular position encoder.

A display device, for example a diode or a display, can then be fitted in the further housing and indicate whether a safe function is active is. If necessary, it is clearly visible to the user that there is an error.

Furthermore, a reset switch for resetting the safety device can be attached to the further housing. The engine can then be easily restarted after a stop.

If the lines from the safety device to the safety sensor are routed via separate channels, separated from high-voltage cables at least 5.5 mm, there is no impairment of safety lines by high-voltage lines.

A second speed signal can be obtained from the motor current or a pulse-duration-modulated signal which controls switching elements of an inverter in the control device and is used as a second "safe" signal. Then only one sensor is required instead of two on the motor shaft, which is cheaper.

The sensor can then be combined with a motor bearing. Such combinations of sensor and bearing are commercially available. This simplifies the manufacture of the electric motor according to the invention.

The invention and its developments are described below with reference to the accompanying drawings of preferred embodiments and modifications of these embodiments. In the drawings:

1 shows a schematic block diagram of a motor control according to the invention for an electric motor with a safety device according to the invention, 2 shows a modification of the safety device according to FIG. 1,

3 shows a further modification of the safety device according to FIG. 1,

4 shows a third modification of the safety device according to FIG. 1,

5 shows a fourth modification of the safety device according to FIG. 1,

6 shows a device according to the invention for automatically checking the functionality of a safety switching device in the safety device according to the invention and an associated pulse diagram,

7 shows a modification of the test device according to FIG. 6 with an associated pulse diagram,

8 is a generalized block diagram of the test device according to FIGS. 6 and 7 with associated pulse diagrams,

9 shows a circuit diagram of a modified test device according to the invention for the operability of inputs and outputs of one of the safety switching devices shown in FIG. 5 with associated pulse diagrams,

Fig. 10 is a circuit diagram of a further modification of a device for

Checking the functionality of a safety switching device with associated pulse diagrams,

11 is a circuit diagram of a further device according to the invention for testing the functionality of a safety switching device with associated pulse diagrams and Fig. 12 shows schematically an electric motor with an inventive

Motor control in the form of a converter.

1 contains a safety device 4, which is connected to a control device 2, here a converter, and to which a user-side, external, i.e. arranged outside the engine control 1, safety and monitoring circuit 5 is connected. The control device 2 is assigned to the motor 3 and contains a low-current control unit 6 on a card 7 (circuit board) - also called "control card" - and a high-current control unit 8 (also called "power control unit") on a high-voltage current - Control card 9 (also called "performance control card").

The low-current control unit 6 contains a digital signal processor (DSP) 10, which has a pulse duration modulator (PDM) 11 and communicates with a microprocessor (μP) 12 via the connection shown as a double arrow.

The heavy current control unit 8 contains an inverter 13, which has power semiconductor switching elements, here so-called IGBTs (IGBT = Insulated Gate Bipolar Transistor), in a three-phase bridge circuit. Furthermore, the high-voltage control unit 8 contains a switching pulse driver 14, which supplies control connections of the power semiconductor switching elements of the inverter 13 via a number of driver stages corresponding to the number of power semiconductor switching elements for controlling the power semiconductor switching elements. The switching pulse driver 14 contains isolating transformers for a safe, potential-free connection of the low-voltage or low-voltage side to the high-voltage or high-voltage side. The switching pulses are generated by the digital signal processor 10 in conjunction with the microprocessor 12 and their duration is modulated by the pulse duration modulator 11 so that the motor 3 via the inverter 12 as an operating current receives approximately sinusoidal three-phase current, the frequency of which corresponds to the setpoint of the speed. The microprocessor 12 also ensures, among other things, that a device or system, for example a pump or an elevator, is driven in accordance with the load requirements at the respectively required speed. The digital signal processor 10 controls, inter alia, the pulse duration modulation carried out by the pulse duration modulator 11.

A further microprocessor 15 is attached to the card 9. In addition to the processing of measurement signals of currents, voltages, temperatures and the control of a fan, it also serves to test the functionality of the safety device 4, more precisely a safety switching device contained therein. The functionality check essentially consists in determining whether a stop signal or stop command signal, when the motor 3 is supposed to stop when it is supplied from the external safety and monitoring circuit 5 without actually starting again unintentionally, was actually effective. If the motor 3 does not stop after a stop command signal has been given, or if no stop activities are started in the motor control, the microprocessor 15 supplies the microprocessor 12 with a stop signal via a bus connection 16, which is signaled by the microprocessor 12 and the digital signal processor 10 is executed.

The safety device 4 contains, on a card 18, also called an “option card”, a safety switching device 19 with a relay 20, transistors 21 and 22 and a delay device comprising two delay elements 23 and 24, the delay time of which can be set by adjusting devices 25 and 26 is.

The relay 20 has three contacts 27, 28 and 29, which are shown here in the de-energized state of the coil 30 of the relay. The contact 27 is connected to the microprocessor 15 via lines 31, 32. The contact 29 is in the operating circuit 33 of the switching pulse driver 14. The contact 28 is via connections 34 a terminal block 35 on the card 18 connected to a test voltage via the safety and monitoring circuit 5, which is arranged, for example, in a control cabinet 17. The transistor 21 is in series with the coil 30 of the relay 20 at an operating voltage UBI of, for example, 24 V and is connected via "relay" and "earth", which are used to connect a switch 36, here a contact of a relay, in the external security - And monitoring circuit 5 and "earth" serve, and connected via the switch 36 to "earth". A switch 40 in the safety and monitoring circuit 5, which can be actuated to trigger a normal stop signal for stopping the motor 3, is connected to a ramp generator in the microprocessor 12 via a line 41 and a “ramp generator input” connection on the card 7.

Separate output lines 46 of the safety and monitoring circuit 5 are connected to further connections 42 and 43 of the terminal block 35, which on the one hand are each connected to an input of the delay element 23 or 24 for triggering them via a line 44 or 45.

A sensor 48 for measuring the (subsequent) frequency of the switching pulses supplied to the switching pulse driver 14 is connected to a connection 47 of the pulse duration modulator 11 with the switching pulse driver 14 as a measure of the speed of the motor 3. The frequency measurement signal is fed to a further input of the microprocessor 15 via a line 49.

The cards 7 and 18 and their circuit arrangements mounted thereon are connected by a connector 50, here a plug connector, which has connections a, b, c ... g, the connecting lines 31, 32, 33, 37 being outside to simplify the illustration of connector 50 are shown. Instead of a plug connector 50, the connection of the cards 7 and 18 can also be done by means of a cable provided with plug contacts at its ends, in particular a flat cable, between receiving contacts on the cards 7 and 18 are manufactured. Likewise, the cards 7 and 9 or the circuit arrangements mounted on them can be connected by a connector, such as the connector 50, or a plug connection cable. The circuit arrangements arranged on cards 7 and 9 can also be arranged together on a single card (circuit board), so that a connector for connecting cards 7 and 9 can be omitted.

The entire circuit arrangement on cards 7 and 9 is designed such that, when card 18 is not connected, it acts as a normal motor control, here as a converter, without a safety function. If, on the other hand, the card 18 is connected, which is preferably provided from the factory, but is also possible by retrofitting, the function of the motor control 1 or the converter changes from a "normal function" to one with a "safety function", in the present case in the "safe stop" function. The card 18 is therefore also referred to as an “option card” since it additionally enables a security function. The presence of the card 18 is determined by measuring a voltage at one of the terminals a-g, e.g. at connection a, checked. If the card 18 is not connected, a high voltage is present at the terminal a, otherwise a low voltage.

The microprocessor 15 is programmed so that it only performs its usual function in the control loop, here the speed control loop, without the option card 18 and, when the option card 18 is connected, also contributes to the safety function and forms part of the safety device 4 in terms of function.

The safety device 4 can be designed for further safety functions, for example it can respond to an "emergency stop", a light barrier, speed limit value exceeded, safety bus or a signal from other sensors that requires the motor to be stopped. These signals can be supplied from the safety and monitoring circuit 5. As an example, only the response to a stop signal via the switch 40 is shown in FIG. 1 explained, which can be closed, for example, by switching on a relay in the circuit 5 to stop the motor 3.

Thus, a pump, not shown, which is driven by the motor 3 can cause an overflow, which is reported by a sensor and actuates a relay in the circuit 5, which then closes the switch 40 so that the microprocessor 12 via the switch 40 , the line 41 and the ramp generator input connection is supplied with a signal which in the microprocessor 12 triggers a ramp signal generator or an equivalent programmed function of the microprocessor 12, by means of which a rapidly decreasing speed setpoint value Signal, a "ramp signal", in the control unit 6 causes the speed of the motor 3 to decrease correspondingly rapidly until it comes to a standstill or expires due to its inertia after the disappearance of the ramp signal.

Here, the microprocessor 12 passes the ramp signal to the digital signal processor 10, which continuously switches off the pulse duration modulator 11, so that the switching pulse driver 14 and thus also the switching elements in the inverter 13 are finally fed no further switching pulses. Simultaneously with the closing of the switch 40, with the switches 36 and 39 of the safety and monitoring circuit 5 still closed, the trigger inputs of the delay elements 23 and 24 are in each case connected via the lines 46, the connections "delay element triggering" and the lines 43, 44 Trigger signal supplied. In normal operation, the delay elements 23 and 24 keep the transistors 21 and 22 turned on, so that a current flows through the relay coil 30 and the contacts 27, 28 are open, whereas the contact 29 is closed. After the delay time has elapsed, the delay element 23 blocks the transistor 21, so that the relay 20 drops out, the contact 29 is opened and the operating current of the switching pulse driver 14 is interrupted. At the same time, contacts 27 and 28 are closed. The delay time of the delay element 23 corresponds approximately to the duration of the shutdown of the motor 3, including the response delay time of the relay 20. The switching-off or interruption of the operating current of the switching pulse driver 14 therefore takes place when the motor speed is zero or almost zero. Instead of switching off all driver stages, only those can be switched off which control the “upper” or “lower” power switching elements of the inverter 13 connected to the positive or to the negative pole of the operating voltage of the inverter 13.

After its delay time, which is equal to that of delay element 23, the other delay element 24 generates a redundant switch-off signal. This signal blocks the transistor 22, as a result of which the reset input R is supplied with a reset signal (voltage zero), so that the operation of the digital signal processor 10 and the pulse duration modulator 11 is also stopped, and consequently the switching pulse driver 14 also no longer receives switching pulses. Simultaneously with the switch-off signal, the delay element 24 reports back to the safety and monitoring circuit 5 via a "feedback" connection of the terminal block 35 that it has given the switch-off signal. The delay times are available in memory devices of the adjusting devices 25 and 26.

In addition to the stop signal via the switch 40, the control device 2 also receives two further (redundant) stop signals to increase the safety in order to ensure with a high degree of certainty that the motor 3 - after the stop signal has been emitted via the Switch 40 - no operating energy is supplied via the control device 2 or the converter and the motor 3 not only stops, but also does not start again.

The contacts 27 and 28 of the relay 20 serve for feedback and checking that or whether the delay element 23 has actually emitted a switch-off signal. After the relay 20 drops out, the microprocessor 15 checks the switching state of the contact 27 by trying to signal the contact 27 to lead. If the contact 27 passes a signal, the microprocessor 15 interprets this so that the contact 27 is closed and the contact 29 has actually interrupted the operating current of the switching pulse driver 14. The external safety and monitoring circuit 5 conducts the test voltage via the contact 28 of the relay 20 connected to the terminal block 35. If the test voltage is passed, this is interpreted by the safety and monitoring circuit 5 as feedback or confirmation that the contact 29 is open, the control device 2 is supplied with a switch-off signal or the operating current of the switching pulse driver 14 is interrupted, and consequently the motor 3 is lo was stopped.

The microprocessor 15 also checks via line 37 whether the voltage at the relay coil 30 has risen due to the blocking of the transistor 21. If this is the case and contact 27 is also closed, then everything is OK. If the contact 27 has not been closed, there is an error in the safety device 4 and the microprocessor 15 triggers an alarm signal.

In applications with high security requirements, feedback or confirmation signals, such as those given via contacts 27 and 28

20 den, passed to the external safety and monitoring circuit 5, which in turn interrupts the main power supply of the engine control 1 when, contrary to expectations, no feedback signal arrives in the external safety and monitoring circuit 5. In order to prevent premature interruption of the main power supply, the external safety and

25 monitoring circuit 5, a delay element is provided which only allows an interruption in operation after its delay time has expired. Instead of this delay element, a relay with a correspondingly high response delay can also be provided in the safety and monitoring circuit 4 to trigger the interruption in operation.

30 The delay elements 23 and 24 can each be designed as an integrated circuit, for example of the 555 type, which blocks a transistor after the delay time has expired. The delay time can also be predefined, for example in a memory element. However, it can also be set by the user by means of pluggable plug connections on the card 18 or by means of a potentiometer. Alternatively, it can be specified by the external safety and monitoring circuit 5 via the terminal block 35. Furthermore, it is possible to automatically set the delay time dynamically as a function of the speed and / or the inertia of the motor 3. An alternative to training with discrete components is to implement the delay device using software in a microprocessor.

A stop can be triggered without delay via the switches 36 and 39 in the user-side safety and monitoring circuit 5. For example, the user can connect a monitoring switch, for example a light barrier switch, to the "Relay" and "Earth" or "Relay" and "UB ₃ " (UB ₃ = eg 5 V) connections. When actuated, the circuit of the relay coil 30 - without delay by the delay element 23 - interrupted or the resetting of the digital signal processor 10 via its

Reset input R is triggered without delay by the delay element 24. The delay elements 23 and 24 are thereby overridden.

The motor controller 1 according to FIG. 2 is modified compared to the one shown in FIG. 1 in that an additional safety function, the speed monitoring according to the standard IEC 61800-5, is implemented on the option card 18. It is used to monitor the engine speed in order to stop the operation of the control device 2 and thus the operation of the engine 3 as quickly as possible when the speed exceeds a predetermined limit value. The speed and speed monitoring is particularly advantageous when starting up larger systems in order to run the motor 3 to carry out a test of the system or, if maintenance has to be carried out during operation, it can only be operated at, for example, 30% of its nominal operating speed. The speed monitoring device stops the operation of the control device 2 and thus that of the motor 3 as soon as the predetermined speed limit is exceeded.

In order to implement speed monitoring using "safe technology", three speed signals are provided. Two speed signals are generated by directly measuring the speed by means of two speed sensors 51 and 51 'on the motor shaft and the third is derived from the repetition frequency of the pulse duration modulated output pulses of the pulse duration modulator 11 by means of the speed sensor 48 and fed to the microprocessor 15 via a line 49. The speed signal can be derived in a simple manner from the repetition frequency of the switching pulses. One possibility is to measure the voltage at connection 47 and to compare it with a predetermined V / f ratio. The frequency f can thereby be determined. However, this procedure is only possible for converters with V / f control.

On the option card 18, a transistor 52 is connected in series with the transistor 21 and a speed monitor 53 on the output side with the base of the

Transistor 52 connected or integrated with this. On the input side, the speed monitor 53 is connected to the speed sensor 51 via connections “sensor input” of the terminal block 35. The series connection of transistors 21 and 52 forms an OR gate. Therefore, when the delay element 23 blocks the transistor 21 or the speed monitor 53 blocks the transistor 52, the contact 29 of the relay 20 is opened and the operating circuit 33 of the switching pulse driver 14 is interrupted.

As in the exemplary embodiment according to FIG. 1, the redundant delay element 24 and additionally a redundant speed monitor 54 are arranged on the option card 18, one of which is in series with the transistor 22 Transistor 55 blocks when the speed signal of the speed sensor 51 ', which is also supplied to it via connections "sensor input", exceeds the predetermined speed limit value.

In this exemplary embodiment too, the user can stop the operation of the converter and thus of the motor 3 directly by means of the switches 36 and 39 which are closed during operation by opening the switch 36 or 39, with the overdrive of the delay elements 23, 24 and the speed monitors 53, 54 ,

3, the safety device 4 of the exemplary embodiment according to FIG. 2 is expanded by a further safety function "safe bus", the second delay element 24 shown in FIG. 2 and the second speed monitor 54 with the transistors 22 and 55 for simplification - Chung the illustration in Fig. 3 are omitted.

Safety buses are ordinary communication buses that are expanded by a safety function. In this embodiment, the bus professional Safe ^® is provided as a safety bus 56, which is the "safe" version of the so-called "professional" bus. "Profibus" is a well-known bus protocol for the communication buses between system elements such as motor controls and programmable logic controllers (PLC). Other buses, such as CANopen Safety, AS-i Safety at Work, Device-net Safe, Interbus Safety, also have so-called "safe technology". The safety bus 56 shown here enables communication via a two-wire cable and is connected to a bus controller 57 via a “safety bus” connection of the terminal strip 35. The redundancy of a shutdown signal via the safety bus 56 is ensured by two microprocessors 58 and 59. The bus controller 57 monitors the communication. If an error occurs somewhere in a factory and the motor 3 installed there or remotely has to be stopped, the safety bus 56 and the "safety bus" connection open the option card 18 transmit a stop signal to the bus controller 57, and from this further via the microprocessor 58 and the microprocessor 59 via a connection 60 to the microprocessor 12 on the card 7, which in turn supplies the reset input R with a reset signal, so that the energy supply to Motor 3 is interrupted.

With the transistors 21 and 52, a further transistor 61 is connected in series in the circuit of the relay coil 30. The microprocessor 58 supplies the transistor 61 with a further (redundant) stop signal, so that the transistor 61 is blocked and the relay 20 drops out.

Thus, two stop signals are generated by the safety bus 56, which ensure that the motor 3 stops safely.

The microprocessor 12 can also be programmed and connected so that it also checks the functional reliability of the relay 20 and the signal transmission paths of the safety device 4. The microprocessor 58 can also be programmed to check the signal transmission over the safety bus using a CRC (Cyclic Redundancy Check) method.

In the exemplary embodiment according to FIG. 4, in contrast to the exemplary embodiments according to FIGS. 1 to 3, no microprocessor is provided on the card 9. Rather, the function of the microprocessor 15 is included in that of the microprocessor 12 by appropriate programming. It is therefore possible, in the event of a defect in the power control unit 8, to replace the card 9 with the power control unit 8 without the microprocessor 15.

Furthermore, the relay 20 has only the two contacts 28 and 29. The contacts 28 and 29 are closed in normal operation with the current-carrying relay coil 30 and connect the operating voltage U _B2 to the switching pulse driver 14, here the primary-side switching pulse driver 14ι of the switching pulse driver 14 divided into the primary-side and a secondary-side switching pulse driver 14 _2. The primary-side switching pulse driver 14ι and the secondary-side switching pulse driver 14 ₂ are inductively coupled via a transformer 62 for potential isolation ,

The safety and monitoring circuit 5 contains, in addition to the switches 36 and 40, further switches 63, 64 and 65. The operating voltage U.sub.4 is connected to one connection of the switches 36, 63 and 64. The other connections are the switches 63 and 64 connected to a trigger input of the delay elements 23 and 24 via the connections "delay element triggering" of the terminal block 35. The other end of the switch 65 is connected to the one input of an INHIBIT element 66 via the "safety channel II" connection. The delay element 24 is connected on the output side to the other input of the INHIBIT element 66. The output of the INHIBIT element 66 is connected to the reset input R of the pulse duration modulator 11 or the DSP 10 and via an isolating stage 68, here a high-impedance resistor, to an input of the microprocessor 12. The line 33 is also connected via an isolating stage 67 to an input of the microprocessor 12. A sensor 69 measures the voltage at the connection 47 and feeds the measured value via a line 70 to a converter 71 on the card 18. The output of the converter 71 is connected to the safety and monitoring circuit 5 via a “safety feedback II” connection of the terminal block 35. The converter 71 converts the PDM signals into an ON or 5 signal.

The mode of operation of the exemplary embodiment according to FIG. 4 is largely the same as that of the previous exemplary embodiments. When a stop signal is supplied to the safety and monitoring circuit 5, the switch 40 closes and the ramp generator in the microprocessor 12 is switched on via the switch 40, so that the motor 3 is shut down. At the same time, switches 63 to 65 are closed. As a result, the delay elements 23 and 24 are triggered and the INHIBIT element 66 is supplied with a signal, through which the reset input R is supplied with a reset signal. After the delay time of the delay element 23 has elapsed, the relay 20 drops out. By dropping the relay 20, the switches 28 and 29 are opened so that the operating voltage U _{ß2 of} the switching pulse driver 14ι is switched off and the microprocessor 12 receives a signal via the isolating stage 67. The opening of the switch 29 is confirmed by this signal. After the delay time of the delay element 24 has elapsed, it outputs a further reset signal to the reset input R via the 0 INHIBIT element 66, which resets the digital signal processor 10 and the pulse duration modulator 11.

Via the isolating stage 68, the reset signal is additionally fed to the microprocessor 5 12, which needs this signal in order to carry out a correct start after the control device 2 or the converter has been switched off. After receiving a reset signal, the microprocessor 12 stores relevant process data which are used when the system is restarted. The isolators 67 and 68 are used to separate the safe signal electronics from normal operating electronics. The processor 12 monitors the security channel II to determine whether a stop signal was emitted via this channel. An electronic fault in the microprocessor 12 should not be able to cause the shutdown signal to not arrive on the safety channel II, which e.g. may be the case when the potential at the microprocessor 12 undesirably drops to ground potential. In the 5 simplest case, the isolator is a high-impedance resistor.

The sensor 69 measures the voltage at the connection 47 and feeds the measured value to the converter 71 on the card 18. This compares the measured value with a reference value, and if the measured value is below the reference value, then the converter 71 reports the safety and monitoring circuit 5 via the Connection "Security feedback II" that a reset signal was actually issued and no switching impulses occur.

In the exemplary embodiment according to FIG. 5, the delay elements 23 and 24 provided in the previous exemplary embodiments are each by software, i.e. by appropriate programming of two microprocessors 72 and 73 which are in an exchange connection via a multiple line M. The setting of their delay times is also carried out by means of the adjusting devices 25 and 26. Furthermore, two safety switching devices 74 and 75 are connected to the microprocessors 72 and 73, which can each have only one transistor, as shown, but here several transistors and have resistances if necessary. Possible exemplary embodiments of the safety switching devices 74 and 75 with a plurality of transistors are shown in FIGS. 7, 8, 9 and 10, which will be described later. The operability of these safety switching devices 74 and 75 is checked by the microprocessor 72 or 73 connected to them. As far as their delay function is concerned, these microprocessors 72 and 73 can also be considered functionally as part of the safety switching devices. The security device 4 on the option card 18 o essentially ensures the overall functional reliability, i.e. that of software and hardware. The usual control device 2 is not burdened with the security tasks. In order to achieve this, the necessary "safe" wiring of the control device is carried out at the factory. Copper tracks are applied to cards 7 and 9, which are to carry safety signals for "safe 5 stop", but which are only put into operation when an option card is connected.

An important aspect in this embodiment is that all the essential components belonging to the function of the safety device 4 are arranged on the option card 18, in particular the microprocessors 72 and 73. Their software (program) therefore essentially only needs to be Execution of the safety functions and here also to be coordinated with the test of the safety switching devices 74, 75. The software of the microprocessor 12 and the DSP 10 of the control device 2 therefore essentially only needs to be matched to the control tasks of the control device 2. A change in the software for the operation of the control device 2 can therefore be carried out with regard to the respective application of the motor 3 without having to change the software of the safety device 4, and vice versa. Accordingly, the software for the operation of the control device 2 is stored in a memory part K ₃ , K _{4 of} the microprocessor 12 and the DSP 10 and the software for the operation of the safety device 4 is stored in a memory part Ki, K _{2 of} the microprocessors 72 and 73. Another advantage of the spatial separation of the program memory parts Ki, K ₂ and K ₃ , K ₄ is that if a component of the control device 2 or the safety device 4 is defective, only the defective card 7, 9 or 18 is replaced by a new one needs to be. Because even with this

Exemplary embodiment, the cards 7 and 9 and 7 and 18 are connected by plug connections, such as the connector 50 or pluggable cable (flat cable), which enable simple and quick replacement of the card in question.

4, two safety channels I and II for triggering a safe hold and two safety feedback channels I and II for feedback (confirmation) to the external, user-side safety and monitoring circuit 5 (the 5 to simplify the illustration) that the "safe stop" has actually taken place.

Thus, a speed signal is fed to the microprocessor 72 via the speed sensor 51, the “sensor input” connection of the terminal block 35 and a voltage level adapter SA, which compares it with a stored limit value and an output A1 of the safety switching device 74 Shutdown signal or stop signal feeds. If the speed signal is equal to or greater than the limit value, the safety switching device 74 interrupts the operating voltage U _B2 or the operating circuit 33 of the switching pulse driver 14- |. In addition, the output current of the inverter 13 is measured by a sensor 76 as a measure of the rotational speed and the measurement signal is fed to a converter 77 via a line 78. This converts the current measurement signal I into a frequency f proportional to this as a measure of the speed and also feeds the speed signal to the microprocessor 72. The microprocessor 72 compares the speed signal with the stored limit value and possibly interrupts the operating voltage U _ß2 or the operating circuit 33 of the switching pulse driver 14ι, if this has not yet been done. The microprocessor 72 reports to the safety and monitoring circuit 5 via an isolating amplifier TR and the "safety feedback I" connection of the terminal block 35 whether the operating voltage has been interrupted or not. The signal fed back to the "Security feedback I" connection is also fed via line 78 to the microprocessor 73, which checks whether the security feedback signal has been given. If, contrary to expectations, this was not the case, an error has occurred and the microprocessor 73 reports an error.

Via connections "Activation DSF I (DSF = designated safety function) and" Activation DSF II "of the terminal block 35, the external safety and monitoring circuit 5 can also switch off operations depending on further monitoring functions, such as the monitoring of the torque, the temperature or the voltage of the Motor 3 or any other predetermined or desired functions are activated, which in turn effect the "safe stop" of the motor via the microprocessor 72 or the microprocessor 73 and the safety switching device 74. Via connections "safety channel I" and "safety channel" II "can in the same way via the internal delay devices of the microprocessors 72 and 73 shutdown command signals from the external circuit 5 of the respective safety switching device 74 and 75 are supplied.

If the microprocessor 73 is supplied with a switch-off command signal or stop signal via the "DSF II" connection, for which a direct switch-off function is programmed in this example, and via a voltage level adapter SA, the microprocessor 73 actuates the via its output A4 The safety switching device 75 is then fed to the digital signal processor 10 by the safety switching device 75 via the line 38 and the reset input R, and the further generation of switching pulses by the pulse duration modulator 11 is interrupted. As a result, the motor 3 is stopped. The signal at the reset input R is also fed back via line 79 to an input Ei of the microprocessor 72 and via the isolating stage 68 to the microprocessor 12. If no reset signal has occurred after the switch-off command signal has been given, the microprocessor 72 may report this via its output-side isolating amplifier TR and the “safety feedback I” connection of the external safety and monitoring circuit 5 and the microprocessor 73 via the line 78ι as a sign of this, that an error has occurred in the safety device 4 or a defect is present. In all circumstances, it also switches off the motor 3 via the safety switching device 74. In addition, the sensor 48 measures the frequency or speed of the motor 3 at the output of the pulse duration modulator 11 or on the connection 47 and supplies the measurement signal to the converter 71 via a line 80. If the measurement signal does not correspond to a reset signal, the microprocessor 73 reports an error, which it issues via its isolating amplifier TR on the one hand via the “safety feedback II” connection to the external safety and monitoring circuit 5 and on the other hand via a line 81 to the Microprocessor 72 forwards. The microprocessors 72 and 73 therefore mutually carry out the same checks and always check each other. A voltage sensor 82 also measures the voltage U _ß2 at the operating voltage input of the switching pulse driver 14ι via a line 83 after the safety switching device 74 has been blocked. If the operating voltage U _{β2 is} still present, the voltage sensor 82 signals this to the microprocessor 73 as an "error". The microprocessor 73 then issues a stop signal via the safety switching device 75 and at the same time informs the microprocessor 72 that it must now be switched off.

The voltage at the operating voltage input of the switching pulse driver 14ι is also supplied to the microprocessor 12 via the isolating stage 67 for checking.

After activating a designated safety function, this function can be reset via a “triggering” connection in the terminal strip 35. After that, the motor control works again in normal operation.

As described above, speed signals are derived from the measurement signals from sensors 76 and 48 and compared with a limit value. In a special version, these two speed values are compared with one another. For this purpose, two of the three PDM signals of the pulse duration modulator 11 are fed to a low-pass filter. The filter generates a sine signal, which is fed to a Schmitt trigger, which converts the sine signal into a pulse signal. The pulse signal, the pulse repetition frequency of which corresponds to the speed, is supplied to the microprocessor 73. The second speed signal to be used for the comparison is obtained from the motor current. The measurement signal is converted into a pulse signal by a Schmitt trigger and fed to the second microprocessor 72. The microprocessors compare the two speeds, and if the difference is outside an allowable range, the motor controller is stopped. Alternatively, the intermediate circuit current can be measured as a measure of the speed. This function can be used for the speed monitoring function. A "safe" speed signal can thus be obtained, so that a speed sensor on the motor shaft can be dispensed with.

5 Also in the embodiment according to Fig. 5 through the terminal "safety bus" of the terminal board 35 of the safety bus 56, here the safety bus professional Safe ^® is connected, the information again from the bus controller 57 (see Fig. 3) are checked to see whether they contain an error or represent a shutdown command signal. If necessary, the bus controller 57 triggers a stop of the motor via the microprocessor 73 and the safety switching device 75 or via the microprocessor 72 and the safety switching device 74. The required delay time can also be sent to the microprocessors 72, 73 via the bus 56.

5 If switching elements for switching off a relay or any other consumer are connected in series with it, they cannot be switched off during operation to check whether they continue to function. This would be like a Halt command. Nevertheless, it is still necessary to once a minute to check the functionality of the o switching elements in "safe technology".

6 shows a circuit diagram of a device for automatically checking the functionality of a safety switching device, by means of which, as a function of at least one shutdown signal, a safety and / or monitoring device, here the safety and monitoring circuit 5 according to FIG. 1 to 3, in the event of danger or for safety reasons, the operation of a consumer, here the motor 3, can be switched off. The test device is described using the example of the safety switching device shown in FIG. 3, which has the relay 20 and the switching elements connected in series therewith, here the transistors 21, 52 and 61, and with the delay element

23, the speed monitor 53, the microprocessor 15 and the microprocessor processor 58 is connected. The collector of the npn transistor 61 connected to the relay 20 (or its coil 30) is additionally connected to the operating voltage UBI and its emitter is connected to "earth".

The test device essentially consists of a pulse generator 88 with a number corresponding to the number of switching elements (transistors), here three, of outputs and logic elements 89, 90 and 91. AND and NOR elements are shown as logic elements. However, it can also be only AND gates, depending on whether the blocking signals of the transistors which are always conductive in normal operation are to be triggered by 1 signals or O signals on the input side of the logic gates. In the present case there are 1 signals.

The pulse generator 88, which can be embodied including the logic elements in the microprocessor 58, cyclically generates 1 signals in succession at its outputs as test or switching pulses Pi, P ₂ and P ₃ , each via one of the logic elements 89, 90 and 91 in this or another

Sequence of the control connections of the transistors as blocking pulses P _λ , P ₂

and R _{3 are} supplied as shown in Fig. 6 (b). The duration of the switching pulses Pi, P ₂ and P ₃ is different and can be, for example, 2 μs, 4 μs and 6 μs. The duration is therefore shorter than the response delay of the relay 20, which can be approximately 20 ms. The relay therefore does not drop out in the event of such a short interruption in its circuit, so that its contacts maintain their respective switching state, "on" or "off" or "closed" or "open". In contrast, the voltage U _R at the relay coil can drop completely or only slightly at each blocking pulse P _γ , P ₂ and P ₃ , as shown in FIG. 6 (b). According to FIG. 6 (b), it decreases completely to zero with each blocking pulse, but only briefly according to the duration of the respective blocking pulse. A microprocessor, here the microprocessor 15, which is programmed according to a discriminator, or a corresponding one Trained discriminator, who constantly checks the voltage UR on the relay coil to determine whether it drops briefly or not, recognizes a brief decrease or fluctuation in the voltage UR as an error-free function of the transistors. However, if at least one of the transistors remains conductive due to a defect and does not respond to blocking pulses, the voltage U _R at the relay coil does not disappear with every blocking pulse, and the discriminator or microprocessor 15 recognizes this as an error in one of the transistors and signals this fault state of the safety and / or monitoring device, here the safety and monitoring circuit 5, and stops the engine control. Since the duration of the blocking pulses is of different lengths, the discriminator also recognizes which of the transistors is defective since the voltage U _{R is} applied to the relevant transistor, for example the blocking pulse P ₂ to the transistor 21, during the period in which a blocking pulse is emitted. would not change, ie would remain constant. This 5 check is possible in principle to determine a blown transistor, ie a transistor that represents a short circuit. Independently of this, the microprocessor 58, the delay element 23 and the speed monitor 53 also, as in the case of FIG. 3, generate redundant shutdown signals after a stop signal, which are each supplied to one of the NOR elements (as 1 signals).

In general, this principle of testing the functionality of a switching element is based on the utilization of the response delay of a consumer, here the relay, with which a faster responding switching element is switched in 5 rows, which in normal operation assumes a first switching state in which the consumer is switched on (live ) and, in the event of danger, can be switched to a second switching state in which the operation of the consumer is switched off, the switching element being able to be switched to the second switching state cyclically in normal operation for a duration which is o shorter than the response delay of the consumer to a switch-off process , It is advantageous if at least one further switching element is provided, which assumes a first switching state in normal operation, in which the consumer is switched on, and can be switched to a second switching state, in which the operation of the consumer is switched off in the event of danger, and when the switching elements in normal operation are cyclically in succession for a period in the second switching state are switchable, which is shorter than the response delay of the consumer to a shutdown process. If the switch-off time of the switching elements is different, it can be determined which switching element is possibly defective. In general, the consumer can be a relay by means of which the operation of a second consumer can be switched off.

The general principle of the above-described device for testing the functionality of the transistors 21, 52 and 61 or corresponding electronic switching elements which are connected in series with another consumer with a response delay is shown in FIG. 7.

According to FIG. 7, the consumer consists of an ohmic resistor R and a capacitor connected in series therewith, from which the operating voltage UB for a safety channel is tapped, the series circuit comprising the consumer and the transistors at a constant DC voltage of, for example, 24 V lies. In this case, the voltage drop UR across the ohmic resistor R is tapped as the test voltage.

The safety switching device, consisting of the transistors, shutdown signal transmitters (safety bus, speed monitor and delay element) as well as the test pulse generators (pulse generator (IPG) 84 and logic elements 89-91) are shown schematically in FIG. 7 (a) in the form of functional units. 7 (b) shows the time course of the test voltage U _{R across} the resistor R. FIG. 8 further generalizes the principle illustrated in FIGS. 6 and 7. Thereafter, instead of the special switch-off command transmitters, such as speed monitors or delay elements, other switch-off command transmitters can also be used, which, because of other safety functions, are monitored by the safety and monitoring circuit 5 are, at the outputs Aι, A ₂ , A _3, for example, of the microprocessor 72 causing shutdown signals which are fed to a safety switching device, for example the safety switching device 74. Test switching pulses P _x , P ₂ and R ₃ at the outputs Ai, A ₂ and A ₃ in the chronological order and duration t) between the switch-off signals for testing the functionality of the switching elements Si, S ₂ , S _{3 of} the safety switching device, t ₂ and t ₃ according to the three lower diagrams in Fig. 8 (b) or in any order and supplied to the respective switching element Si, S ₂ and S ₃ . At the common output of the series connection of the switching elements S ^, S ₂ and S ₃ , which corresponds to the lines 33 and 83 in FIG. 5, the signal curve to be measured by the sensor 82 and shown in the top diagram in FIG. 8 (b) then occurs ( Voltage or current curve) when the function of all switching elements Si to S _{3 is} error-free.

Depending on this course, "no error" or "error" is reported here by the microprocessor 73 to the safety and monitoring circuit 5, as was described with reference to FIG. 6.

FIG. 9 shows an exemplary embodiment of the safety switching device 75 according to FIG. 5, which is checked for functionality during normal operation by the microprocessor 73 via its outputs A ₄ and A ₅ and for switching off the motor 3 via both outputs A. ₄ , A ₅ receives a shutdown signal at the same time. The microprocessor 75 can therefore be considered functionally as part of the test device and as part of the safety switching device. The safety switching device 75 contains a controllable circuit comprising two ohmic resistors 92 and 93 connected in series and a transistor 94 connected in series with the resistors 92, 93. This circuit lies between the output A _{4 of} the microprocessor 73 and "earth". Furthermore, the safety switching device 75 contains a second controllable circuit comprising two ohmic resistors 95 and 96 connected in series and a transistor 97 connected in series with the resistors 95, 96. This circuit lies between the output A ₅ and “earth”. The connection between the resistors 92 and 93 and the connection between the resistors 95 and 96 form the outputs of the two circuits. The outputs are connected to one another and form the output Aβ of the safety switching device 75. The operating voltage UBI also has two further series connections, each of which has two ohmic resistors 98 and 99, or 100 and 101, between each of which a transistor 102 and 103 lies. The transistor 102 is controlled via an ohmic resistor 104 from the output A ₄ and the transistor 103 via an ohmic resistor 105 from the output A ₅ . The transistors 102 and 103 control one of the transistors 94 and 97 via an ohmic resistor 104 and 105, respectively. In normal operation there is a voltage with constant level PK at output As.

During the test phase, the microprocessor 73 generates three-stage signals at its outputs A ₄ and A ₅ , as shown in the two lower diagrams of FIG. 9 (b). These signals are out of phase with respect to an average voltage U and each have a first switching pulse SP ₁ or SP ₃ and a second switching pulse SP ₂ or SP ₄ , which are repeated cyclically as long as the test phase continues. The switching pulses are generated in the microprocessor 73 via two transistors connected in series and alternately switched through. As long as none of the switching pulses SP ₁ to SP occurs, the voltage U is at the outputs A ₄ and A ₅ , so that both transistors are blocked and there is also a relatively high voltage at the output A ₆ . If on the other hand, the falling pulse SPi occurs at output A ₄ , the rising pulse SP ₃ is simultaneously generated at output A ₅ . Transistors 102 and 94 become conductive by pulse SP1, while transistors 103 and 97 are simultaneously blocked by switching pulse SP ₃ . The voltage at the output A ₆ decreases to a lower test level PP because the resistors 93 and 96 are not connected in parallel during the duration of the switching pulses SP ₁ and SP ₃ , ie the on-period of the transistor 94 when the transistor 97 is blocked. The microprocessor 72 recognizes this as "error-free" of the safety switching device 75.

The same applies when the switching pulses SP ₂ and SP _{4 are} output, transistor 94 now being blocked and transistor 97 being conductive. However, if one of the transistors 93 and 94 is short-circuited due to a fault, then the signal at the output Aς does not have the ripple according to the uppermost diagram in FIG. 9 (b). Rather, the curve shape is changed, and the microprocessor 72 detects this changed curve shape and thereupon outputs a signal “error” to the safety and monitoring circuit 5, or a stop signal via the safety switching device 74.

However, if the safety switching device 75 is in order and the motor 3 is to be switched off on the basis of a switch-off command signal sent to the microprocessor 73 by the safety and monitoring circuit, the microprocessor 73 simultaneously generates a signal at both outputs A ₄ and A ₅ , so that both transistors 94 and 97 become conductive and a low voltage at output A ₆ of safety switching device 75

PN occurs, which is supplied as a reset signal to the reset input R, so that the motor 3 is switched off.

The safety switching device 75, including the microprocessors 73 and 72 provided for its testing, can also be used for any other consumer which is provided with a safety switching device for switching off. but do not have a control device, such as the control device 2, can be used. Instead of the microprocessor 73, another circuit, for example a corresponding pulse generator with the same test function as that of the microprocessor 73 and, instead of the microprocessor 72, a discriminator or comparator for distinguishing the levels PK, PP and PN can be used.

10 shows an exemplary embodiment of the safety switching device 74 and schematically of the microprocessor 72, which together form a device for automatically checking the functionality of the safety switching device 74. At the same time, they form part of the security device 4 on the option card 18.

10, the safety switching device 74 contains a first controllable circuit from the series connection of an ohmic resistor 106 with a transistor 107 and a second controllable circuit from the series connection of an ohmic resistor 108 and a transistor 109 the transistor 109's outputs of the two circuits are connected to one another and together form the output A of the safety switching device 74. The output A ₇ is connected via line 33 to the operating voltage connection of the switching pulse driver 14ι and via line 83 to the Voltage sensor 82 connected. Two further series circuits each consisting of two ohmic resistors 110 and 111 or 112 and 113 and a transistor 114 and 115 connected in series are connected in parallel between the operating voltage U _ß2 and "earth". The connection of the resistors 110 and 111 is connected to the control connection of the transistor 107 and the connection of the resistors 112 and 113 to the control connection of the transistor 109.

In this exemplary embodiment, the microprocessor 72 generates a (high) signal ON at its outputs Ai and A ₂ in normal operation, so that both trans sistors 109 and 107 are conductive, and during a test phase each a test switching pulse SP ₄ or SP ₅ , which is supplied to the control terminal of the respective transistor 114 or 115. The test switching pulses SP ₄ and SP ₅ are staggered in time without mutual overlap and are repeated during the test phase. Thus, when the test switching pulse SP _{4 occurs} at the output A _{1 of} the microprocessor 73, the transistors 114 and 107 which conduct during normal operation at high output voltage at the outputs A ₂ and A _{1 are} blocked, while the transistors 109 and 115 remain conductive. The voltage at output A ₇ therefore only decreases slightly from the constant level PK to the test level PP. The takes between the two test switching pulses

Voltage at output A ₇ again towards PK in order to decrease again somewhat at the following test switching pulse SP ₅ at output A ₂ of microprocessor 73. The voltage at output A therefore fluctuates only slightly during the test phase. The slight fluctuation in the output voltage is passed on from the connected voltage sensor 82 to the microprocessor 73, which interprets the fluctuation as an error-free state of the safety switching device 74. If the fluctuation does not occur or the curve shape deviates from the curve shape in the test phase, this is recognized as an error in the safety switching device 74. If, on the other hand, the consumer, here the motor 3, is to be switched off in normal operation, the microprocessor 72 simultaneously generates a low signal "OFF" at both outputs A ₁ and A ₂ . As a result, the transistors 107 and 109 are blocked at the same time, so that the driver 14ι the operating voltage is removed and the motor 3 stops. If, on the other hand, the voltage at output A ₇ fluctuates only with a small amplitude during a test phase in normal operation, the switching pulse driver 14 1 and thus the motor 3 remain in operation.

The resistors 106 and 108 can preferably be set automatically as a function of the load, ie they can be replaced by smaller circuit arrangements which match the respective resistance as a function of the load current, for example the switching pulse driver 14 set the best value. This has the advantage that the resistors 106 and 108 do not have to be dimensioned differently for each application when designing the safety switching device 74.

11 shows in principle a circuit arrangement of a test unit 116 in a device 117 (FIG. 5) for automatically testing the functionality of a safety switching device. In the present case, the input connections of the microprocessors 72 and 73 are checked for their functionality, the microprocessors 72 and 73 generalized as that or as part of a safety switching device. The test unit 116 itself is also tested.

The reason for this test is essentially as follows: In the embodiment according to FIG. 5, the input connections of the microprocessors 72 and 73 are supplied with switch-off signals via the connections of the terminal block 35 on the option card 18. It should be ensured that these shutdown signals are actually received and processed by the microprocessor 72 or 73 concerned. So-called "sleeping errors" should be determined. Such an error can e.g. caused by an input connection of the microprocessors over a longer period, e.g. several years with the same signal, e.g. a constant DC voltage of 24 V, is loaded without the user triggering a stop signal or switch-off signal. In the worst case, the error is only determined when a "safe function" is to be activated. This would not be tolerable, because another error could occur which prevents the safety device 4 from working.

In order to avoid such a case, the input connections of the microprocessors 72 and 73 are automatically controlled internally without influencing the connections of the terminal block 35. A test unit such as the test unit 116 shown in FIG. 11 is provided for each input terminal of the microprocessors 72 and 73, and each test unit can be controlled individually.

The output ports of the microprocessors are also tested. This happens because the one microprocessor emits a short signal which is controlled by the other microprocessor.

The test unit 116 according to FIG. 11 is connected to a connection of the terminal block 35 (FIG. 5) via a voltage level adapter SA, which contains an ohmic voltage divider. The connection has been omitted to simplify the illustration in FIG. 5. The test unit 116 has two further inputs E ₃ , E ₄ , to which test switching pulses SPβ, SP ₇ which are staggered in time are supplied by a pulse generator in the microprocessor 72. The pulse generator is implemented by programming the microprocessor 72 accordingly. The test unit 116 also has an output As, which is connected to an input connection of the microprocessor 73 or the safety switching device via a voltage level adapter SA.

11 (a) contains a first series circuit comprising a first transistor 118, a second transistor 119 polarized in the same direction with the first transistor 118 and two diodes 120, 121 polarized in the same direction with the transistors 118, 119 between the transistors 118, 119. It also contains a second series circuit comprising two ohmic resistors 122, 123, the connection of which is connected to the control connection of the first transistor 118, and a third transistor 124. The control connection of the second transistor 119 forms the input E ₄ , the control connection of the third transistor 124 the input E ₃ and the connection of the diodes 120, 121 the output A ₈ . The test switching pulses SP ₆ and SP are repeated cyclically at predetermined times and fixed intervals, the test switching pulses SP ₇ occurring between the test switching pulses SPβ and vice versa. Each time a test switching pulse SPβ is received by microprocessor 72 at input E ₃ , a high output pulse SP ₈ occurs at output Aβ of test unit 116 and each time a test switching pulse SP is received at input E ₄ by microprocessor 72, a low output pulse SP ₉ occurs. The output pulses SPβ and SP ₉ are passed on from the microprocessor 73 via the multiple line M to the microprocessor 72. The microprocessor 72 then checks whether it has a high output pulse SPβ of the test unit 116 at or at the time of the output of a test switching pulse SP ₆ and a low output pulse SP _{9 of} the test unit 116 at or at the time of the output of a test switching pulse SP ₇ receives. If the microprocessor 72 does not receive a corresponding output pulse SP ₈ or SPg when a test switching pulse SP ₆ or SP _{7 is} emitted, it generates a signal “error” which is reported back to the safety and monitoring circuit 5 or gives a stop signal to the Control device. In contrast, it generates a "no error" signal if it receives a corresponding output pulse SP ₈ and SP ₉ from the test unit 116 each time a test switching pulse SP ₆ and SP _{7 is} emitted.

The application of the high and low output pulses SPβ and SP _{9 of} the test unit 116, which are supplied to the microprocessor 72, is necessary because it is not known beforehand whether the user uses a high or low shutdown signal in normal operation. The test rather ensures that the microprocessor can process both low and high shutdown signals. This prevents short circuits or interruptions from being detected in the input connections.

The microprocessor 72 can also have its own input connections via test units, such as the one connected accordingly to its input connections Test unit 116, check for functionality, although this is not shown in FIG. 5.

The test should be performed as often as necessary, but only relatively briefly and rarely compared to using a shutdown function because the user shutdown signal cannot be detected during the test. During the test, the input resistance, as seen by the user, is reduced, for example from 4 kOhm to 2 kOhm. However, this seems acceptable because the user often uses a relay.

12 shows the construction of the electric motor 3, which is designed as a three-phase three-phase motor and is provided in a known manner with the control device 2, which is designed here as a converter and the low-current control unit 6 and the high-current control unit 8 with the inverter 13 in a housing 125 of the motor 3. The housing 125 consists of three housing parts 126, 127 and 128. The stator with the stator winding 129 and the rotor 130 are arranged in the housing part 126. The shaft 131 of the rotor 130 is mounted in bearings 132 and 133 and drives a fan 134 in the housing part 128. The housing part 127 is fastened to the housing part 126 and is accessible from the outside after loosening a cover 135. The control device 2 and the safety device 4 connected to the control device 2 by a connector (not shown) (connector or flat cable with connector parts) are arranged within the motor, ie its housing part 127. The safety device 4 is mounted on a separate card 18, while the low and high current control units 4 and 6 are either mounted on separate cards 17 and 8 or together on one card (circuit board). The safety device 4 can also be arranged together with the control device 2 on a single card. The sensor 51 for measuring the speed is arranged in the motor 3, ie in its housing unit consisting of the housing parts 126 and 128. With the senso Ren 136 and 137 further possible locations of the sensor are shown. Under certain circumstances, several sensors can be used.

The sensor 51 has only one task, namely to contribute to a "safe function". It is therefore connected to the safety device 4 inside the motor 3 (its housing 125). If the speed of the motor 3 is also to be regulated, an additional speed sensor can be provided, which is usually mounted on the shaft 131 outside the motor.

The sensor 51 can be a conventional sensor or a sensor specially designed for safety purposes, here for measuring the speed in order to compare it with a limit value.

The connecting lines between the safety device 4 and the sensor 51 arranged inside the motor are all laid inside the motor, insofar as it is a "safety sensor". The user therefore does not have to worry about the wiring.

Claims

claims

5 1. Electric motor with an integrated electronic control device (2) and a sensor connected to it, characterized in that the sensor (51) is arranged within a motor housing (126, 128) and serves alone or additionally as a safety sensor and with one in one further housing (127) arranged on the motor housing and 0 arranged electronic safety device (4) is connected, which is connected to the integrated control device (2).

2. Electric motor according to claim 1, characterized in that the sensor is a speed sensor which is attached to the motor shaft (131). 5

3. Electric motor according to claim 2, characterized in that the speed sensor is a redundant sensor and consists of two independent speed meters (51, 51 ').

4. Electric motor according to claim 1, characterized in that the safety device (4) on a first card (18) in the further housing (127) and the control device (2) is applied to at least one second card (7).

5 5. Electric motor according to claim 1, characterized in that the safety device (4) and the control device (2) in the further housing (127) are applied to a common card.

6. Electric motor according to claim 1, characterized in that the safety device o (4) has electrical connections (35) through a

Wall of the further housing are accessible and the connecting ex- Enable ternal signal lines (39, 56), for example signal lines of an emergency stop switch or a communication bus (56).

7. Electric motor according to claim 6, characterized in that security 5 feedbacks (36) from the security device (4) to external units, e.g. a programmable logic controller (PLC) or an external safety device (5) via which electrical connections are conducted.

0 8. Electric motor according to claim 1, characterized in that the safety device (4) contains two microprocessors (72, 73) which mutually monitor each other for errors and continuously the operability of safety switches (61, 21, 52) and input and output connections Check (A1-A5) the microprocessors. 5

9. Electric motor according to claim 2, characterized in that the safety device (4) has the function "speed monitoring" and switches off the control device (2) when a speed limit is exceeded. 0

10. Electric motor according to claim 1, characterized in that the safety sensor is a torque sensor or angular position encoder.

11. Electric motor according to claim 1, characterized in that a display device 5, e.g. a diode or a display, in the further housing

(127) is attached and indicates whether a safe function is active.

12. Electric motor according to claim 1, characterized in that a reset switch for resetting the safety device (4) on the widen- o ren housing (125) is attached.

13. Electric motor according to claim 1, characterized in that the lines from the safety device (4) to the safety sensor (51) via separate channels, separated from power cables at least 5.5 mm, are performed.

14. Electric motor according to claim 1, characterized in that a second speed signal from the motor current (77) or a pulse duration modulated signal (71) is obtained, which controls switching elements of an inverter (13) in the control device (2), and as a second safe rotation - Number signal is used.

15. Electric motor according to claim 1, characterized in that the sensor is combined with a bearing of the motor (3).