546
Appendix 5.4.3 Range check processing for index-modified devices
(1) Device range check
Error check processing at index modification of devices has been enhanced for the Universal model QCPU.
Each index-modified device range is checked, and if the check target device is outside the device range before
index modification, the CPU module detects "OPERATION ERROR" (error code: 4101).
For details on the index-modified device range check, refer to the following.
MELSEC-Q/L Programming Manual (Common Instruction)
In Example 1), when the contact (M0) is on and the value -1 or less is specified in Z1, the device D0Z1 is included
in the C device range, exceeding the D device range, as shown in the following figure. As a result, "OPERATION
ERROR" (error code: 4101) will be detected.
When an error is detected, check the index modification value (value of Z1 in the above example) and remove the
error cause.
Examples of the cases where an error is detected and not detected are shown below.
Ex.1)
Detecting "OPERATION ERROR" (error code: 4101) by error check processing at index modification of
devices (QnU(D)(H)CPU, QnUDE(H)CPU, LCPU)
C0
C device area
D device area
W device area
D0
W0
When the value of Z1 is -1,
the device is included in the
C device range, resulting in an error.
To Next Page
Loading...
Need help?
General
