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COMRD(P)
(2) If no comment has been registered for the device specified by despite the fact that the
comment range setting is made, all of the characters for the comment are processed as
"20
H
" (space).
(3) The device number plus 1 where the final character of is stored differs depending on the
ON/OFF status of SM701 (number of characters to output select signal).
When SM701 is OFF : Does not change
When SM701 is ON : Stores "0"
(4) When a comment is read, SM720 turns ON for one scan after the instruction is completed.
SM721 turns ON during the execution of the instruction.
While SM721 is ON, the COMRD(P) instruction cannot be executed. If the attempt is made,
no processing is performed.
1. The device comment used in the COMRD(P) instruction uses a comment file
stored in a memory card and the standard ROM.
Comment files stored in the program memory cannot be used.
2. Set the comment file used for the COMRD(P) instruction in "PLC file setting" in
the PLC parameter dialog box. If the comment file to be used is not set in the
PLC file setting, device comments cannot be output with the COMRD(P)
instruction.
3. The COMRD(P) instruction cannot be executed during the interrupt program.
No operation if executed.
Operation Error
(1) In any of the following cases, an operation error occurs, the error flag (SM0) turns ON, and
an error code is stored into SD0.
• The comment is not registered to the device number specified by . (Error code: 4100)
• The device number specified by is not a word device. (Error code: 4101)
• The device specified by exceeds the range of the corresponding device.
(For the Universal model QCPU only.) (Error code: 4101)
S
D
S
D
D