Siemens SIMATIC S7-1200 - 8.8.6 RE_TRIGR (Restart cycle monitoring time)

Basic instructions
8.8 Program control operations
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
309
Note
Password protect CPU access levels with strong passwords. Strong passwords are at least
ten characters in length, mix letters, numbers, and special characters, are not words that can
be found in a dictionary, and are not names or identifiers that can be derived from personal
information. Keep the password secret and change it frequently.
Table 8- 140 Condition codes
RET_VAL
(W#16#...)
Description
0000
No error
8090
The instruction is not supported.
80D0
The password for fail-safe is not configured.
80D1
The password for read/write access is not configured.
80D2
The password for read access is not configured.
80D3
The password for HMI access is not configured.
8.8.6
RE_TRIGR (Restart cycle monitoring time)
Table 8- 141 RE_TRIGR instruction
LAD / FBD
SCL
Description
RE_TRIGR();
RE_TRIGR (Re-trigger scan time watchdog) is used to extend the maximum
time allowed before the scan cycle watchdog timer generates an error.
Use the RE_TRIGR instruction to restart the scan cycle monitoring timer during a single scan
cycle. This has the effect of extending the allowed maximum scan cycle time by one
maximum cycle time period, from the last execution of the RE_TRIGR function.
Note
Prior to S7
-1200 CPU firmware version 2.2, RE_TRIGR was restricted to execution from a
program cycle OB and could be used to extend the PLC scan time indefinitely. ENO =
FALSE and the watchdog timer is not reset when RE_TRIGR was executed from a start up
OB, an interr
upt OB, or an error OB.
For firmware version 2.2 and later, RE_TRIGR can be executed from any OB (including start
up, interrupt, and error OBs). However, the PLC scan can only be extended by a maximum
of 10x the configured maximum cycle time.