Fcs Performance
Fcs Performance
Fcs Performance
2 FCS Performance
FCS Performance
If the maximum number of function blocks allowed for the selected template is created or if many
function blocks are run at a faster scanning period than the basic, the performance of the FCS
may be degraded. In the worst case, you may have to divide it into several FCSs or delete some
of the functions. To avoid this, you must estimate and study the FCS performance. The following
section describes the factors that affect the FCS performance and how to calculate the FCS
performance to prevent performance problems.
[Important Note]
650ms or 830ms is the maximum allowance for Control, Data Access, Message Sending
and Other Tasks. Therefore, if 20% spare must be kept for future expansion, consider
650ms*0.8 = 536ms is the higher limit which can be used in engineering phase, in case of
AFF50D. (NOT 1000ms*08=800ms)
Below shows the image of CPU idle time and CPU load time
ESS-CDWG-S601-020202E, Rev. 6 1 of 24
CS 3000/VP ENGINEERING GUIDE 2.2.2 FCS Performance
Basic-scan Processing
Mid-scan Processing
High-scan Processing
CPU Load Time
(Incl. High-scan I/O Processing)
Data Access
1000 msec
Message Sending
Other Tasks
Below are the some important points on the behavior of FCS when CPU load become high:
1. With the CPU load high to an extent that there is not enough CPU time to execute all
required functions in time, completion of the lower-priority tasks is delayed or not
executed.
a. High CPU load will make time-sharing SEBOL execution delayed first.
b. Higher CPU load will make the time-sharing SEBOL not executed at all and the basic-
scan processing delayed next.
c. Further higher CPU load will make the basic-scan processing not executed at all and
the medium-scan processing delayed next.
d. Much further higher CPU load will make the medium-scan processing not executed at
all and the high-scan processing delayed next.
ESS-CDWG-S601-020202E, Rev. 6 2 of 24
CS 3000/VP ENGINEERING GUIDE 2.2.2 FCS Performance
2. With the CPU load high to an extent that the Basic-scan processing is not complete
within four seconds,
a. In this case the I/O value will be its default fall-back value. (Only FIO system. This
situation is equivalent to loss of process control functions.)
b. The System alarm ―FCS Too Heavy Load‖ will be reported.
Control Function
(Incl. Basic-scan IO processing) (Incl. Basic-scan IO processing)
Mid-scan Processing
High-scan Processing
Maintenance Processing
(Incl. Basic-scan IO processing)
1000 msec
High-scan Processing
Data Access
(Incl. Basic-scan IO processing)
Message Sending
Maintenance Processing
Figure 2; Image of CPU under the maintenance operation is in progress with sufficient CPU idle time
ESS-CDWG-S601-020202E, Rev. 6 3 of 24
CS 3000/VP ENGINEERING GUIDE 2.2.2 FCS Performance
Control Function
(Incl. Basic-scan IO processing)
Control Function
Maintenance Processing
Mid-scan Processing
1000 + X msec
Mid-scan Processing
1000 msec
Maintenance Processing
Other Tasks
Figure 3; Image of CPU under the maintenance operation is in progress with insufficient CPU idle time
・LFSC2, KFCS2, FFCS, FFCS-S, and FFCS-L (32 MB main memory): 20 minutes
・LFCS and KFCS (16 MB main memory): 12 minutes
・FFCS-V (128 MB main memory): 5 minutes
3. Online Load:
The actual CPU Load time required depends on the download volume.
The Online load finishes within 1 second.
ESS-CDWG-S601-020202E, Rev. 6 4 of 24