Siemens SIMATIC S5 Manual page 138

Bits 6 and 7: Short circuit identifiers A, B:
Short-circuit detection is only active when:
– a value for minimum temperature difference is entered in byte 2 in
messages 30 to 42
– the manipulated variable is 100% or the hot channel control is in the
open-loop mode in the approach phase
– the setpoint of a controller is not zero and the heating switch is not having an
effect, or having an effect and is on.
– A check is made only after
o
o
Short-circuit detection is not active when:
– cooling controllers have been selected
– self-tuning is currently active
– zero is entered for minimum temperature difference in messages 30 to 42.
The following rules apply:
– If one of these bits is set, the appropriate controller group error bit and the group error bit are
set simultaneously.
– If bit 6 = 1, the output of the controller is disabled.
– The error messages can only be cleared by the commands "PA", "KS" and "AE" of function
block FB 162.
Messages 47 to 63
IP244
C79000–B8576–C860–02
20 x Ta (sampling time) with non-self-tuned controllers
3 x Tu (delay time) with self-tuned controllers
Free
Data Exchange with the Central Controller
4–71