GE PACSystems RX7i - Page 168

Chapter 4. Ladder Diagram (LD) Programming
GFK-2950C February 2018 153
Operands for COMMREQ
Parameter
Description
Allowed Operands
Optional
IN
The reference of the first WORD of the command block.
Variables in %R, %P, %L,
%AI, %AQ, %W, and
symbolic non-discrete
variables
No
SYSID
The rack number (most significant byte) and slot number
(least significant byte) of the target device (intelligent
module).
Note: For systems that do not have expansion racks,
SYSID must be zero for the main rack.
All except flow and
variables in %S - %SC
No
TASK
The task ID of the process on the target device
Constants; variables in %R,
%P, %L, %AI, %AQ, %W, and
symbolic non-discrete
variables
No
FT
Function Faulted output. FT is energized if an error is
detected processing the COMMREQ:
▪ This is a WAIT mode COMMREQ and the CPU does not
support it
▪ The specified target address (SYSID operand) is not
present.
▪ The specified task (TASK operand) is not valid for the
device.
▪ The data length is 0.
▪ The devices status pointer address (part of the
command block) does not exist. This may be due to an
incorrect memory type selection, or an address within
that memory type that is out of range.
Power flow
Yes
COMMREQ Status Word
The CRS word consists of two byte
values, a major code and a minor code.
Refer to the specific device manual for
CRS major and minor codes used by
COMMREQ commands at that device.
00
01
CRS Word
(hexadecimal)
High Low
Minor Error Code (high byte)
Success and Major Error Code (low byte)
COMMREQ Example 1
When enabling input %M0020 is ON, a command block
starting at %R0016 is sent to communications task 1 in
the device located at rack 1, slot 2 of the PLC. If an error
occurs processing the COMMREQ, %Q0100 is set.