Hardware manual PCD7.LRxx-PG5 room controller │ Document 27-653; version ENG07 │ 2019-03-21
Saia-Burgess Controls AG
Watchdog (software)
Room controller/CPU
3-21
3
3.11
Watchdog (software)
A software watchdog (in which the processor monitors itself and the CPU is re-
started in the event of a malfunction or a loop) is sufficient for non-critical applica
-
tions.
The core of the software watchdog is the STL command SYSWR K 1000, which is
also used in the “Software Watchdog” FBox.
Function
When this is output for the first time, the watchdog function will be enabled. This
instruction must then be output at least every 200 ms, otherwise the watchdog will
be triggered and the PCD restarted.
FUPLA FBox example:
FBox Selector -> System Information -> Software Watchdog
Instruction in STL code:
Label
Com-
mand
Operand Comment
SYSWR
K 1000
; Software watchdog instruction
R/K x
; Parameters as per the following table
; K = constant or R = register
; followed by a space.
; x = 0 The software watchdog is
; disabled.
; x = 1 The software watchdog is
;
enabled. If the instruction
;
is not repeated within 200 ms,
;
a cold start is
; initiated.
; x = 2 The software watchdog is
;
enabled. If the instruction
;
is not repeated within 200 ms,
;
XOB 0 is called up, then
;
a cold start is
; initiated.
“XOB 0” call-ups are entered in the PCD history as follows:
“XOB 0 WDOG START”
if XOB 0 was triggered by the software watchdog
“XOB 0 START EXEC”
if XOB 0 was triggered by a supply failure
