she候鸟英文版:siemens PLC function blocks FB41, FB42 and FB43

QUESTION:
What should you watch out for when calling and assigning parameters to the controller
functions in function blocks FB41, FB42 and FB43?
ANSWER:
Function blocks FB41, FB42 and FB43 are contained in the STEP 7 standard library
under PID blocks.
When using these blocks, please pay attention to the points below.
1. FB 41 "CONT_C"
l The controller must be called in a watchdog interrupt OB (e.g. OB35).
l The "CYCLE" parameter corresponds to the sampling time. The time between
block calls must be parameterized here.
l The controller's default setting is manual mode (MAN_ON=true). The control loop
is interrupted.
l In order to switch from manual mode to automatic mode without any jolts, at least
2 block runs need to be performed in manual mode.
l The block should be run once with "COM_RST" = true when the CPU is rebooted.
l The "COM_RST" parameter can be used to block the controller.
2. FB 42 "CONT_S"
l The controller must be called in a watchdog interrupt OB (e.g. OB35).
l The "CYCLE" parameter corresponds to the sampling time. The time between
block calls must be parameterized here.
l The controller's default setting is manual mode (LMNS_ON = true).
l The block should be run once with "COM_RST" = true when the CPU is rebooted.
l The "COM_RST" parameter can be used to block the controller.
l The "PULSE_TM" and "BREAK_TM" parameters are to be configured to a
complete multiple of the "CYCLE" parameter.
3. FB 43 "PULSEGEN"
l The pulse generator must be called in a watchdog interrupt OB (e.g. OB35).
l The block should be run once with "COM_RST" = true when the CPU is rebooted.
l The "CYCLE" parameter corresponds to the sample time. The time between block
calls must be parameterized here.
l FB 43 can only be used in conjunction with FB 41.
l The "PER_TM" parameter must be configured to the sampling time for the
controller (FB41).
l The call time for the FB41 is reached via a clock distributor.