4-154 Series 90-30/20/Micro Programmable Controllers Reference Manual – September 1998 GFK-0467K
4
SVCREQ #13: Shut Down (Stop) PLC Use SVCREQ function #13 in order to stop the PLC at the end of the next sweep. All outputs will
go to their designated default states at the beginning of the next PLC sweep. An informational fault
is placed in the PLC fault table, noting that a “SHUT DOWN PLC” function block was executed.
The I/O scan will continue as configured.
This function has no parameter block.
Example:
In the following example, when a “Loss of I/O Module” fault occurs, SVCREQ function #13
executes. Since no parameter block is needed, the PARM input is not used; however, the
programming software requires that an entry be made for PARM.
This example uses a JUMP to the end of the program to force a shutdown if the Shutdown PLC
function executes successfully. This JUMP and LABEL are needed because the transition to STOP
mode does not occur until the end of the sweep in which the function executes.
|
|LOS_MD %T0001
|
|——| |——————————————————————————————————————————————————————————————————————(↑↑)—
|
| _____
|%T0001 | |
|——| |———————| SVC_|——————————————————————————————————————————————————>> END_PRG
| | |
| | REQ |
| | |
| CONST —|FNC |
| 0013 | |
| | |
| %R1001 —|PARM |
| |_____|
|
.
.
.
|
| END_PRG:
|
|
| [ END OF PROGRAM LOGIC ]
|
Note
To ensure that the %S0002 LST_SCN contact will operate correctly, the PLC will
execute one additional sweep after the sweep in which the SVCREQ function #13
was executed.