Format Of The Svcreq Function; Parameters Of The Svcreq Function; Example Of The Svcreq Function - GE VersaMax PLC User Manual

11.2 Format of the SVCREQ Function

Input/Output
enable
FNC
PARM
ok
%I0001
CONST
00007
%R0001
The Service Request Function
For public disclosure
The SVCREQ function has three inputs and one output.
enable
Function number
Beginning reference
When the SVCREQ receives power flow, the PLC is requested to perform the function
number FNC indicated. Parameters for the function are located beginning at the reference
given for PARM. This is the beginning of the "parameter block" for the function. The
number of 16-bit references required depends on the SVCREQ function being used.
Parameter blocks may be used as both inputs for the function and the location where data
may be output after the function executes. Therefore, data returned by the function is
accessed at the same location specified for PARM.
The SVCREQ function passes power flow unless an incorrect function number, incorrect
parameters, or out-of-range references are specified. Specific SVCREQ functions have
additional causes for failure.

11.2.1 Parameters of the SVCREQ Function

Choices
flow
I, Q M, T, G, R, AI, AQ,
constant
I, Q M, T, G, R, AI, AQ
flow, none

11.2.2 Example of the SVCREQ Function

In the example, when the enabling input %I0001 is ON, SVCREQ function number 7 is
called, with the parameter block located starting at %R0001. Output coil %Q0001 is set
ON if the operation succeeds.
SVC
REQ
FNC
PARM
OK
SVC
REQ
FNC
PARM
Description
When enable is energized, the service request is
performed.
Contains the constant or reference for the
requested service.
Contains the beginning reference for the
parameter block for the requested service.
OK is energized when the function is performed
without error.
%Q0001
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