Debugging And Failure Diagnosis Instructions; Chkst, Chk; Special Format Failure Check - Mitsubishi MELSEC-Q/L Programming Manual

CHKST, CHK

7.10

Debugging and failure diagnosis instructions

7.10.1 CHKST, CHK

Special format failure check

7.10.1
CHKST, CHK
CHKST
CHK
Setting Internal Devices
Data
Bit
––
Function
CHKST
(1) The CHKST instruction is the instruction that starts the CHK instruction.
If the command for the CHKST instruction is OFF, execution jumps from the CHK instruction to the next instruction.
If the command for the CHKST instruction is ON, the CHK instruction is executed.
CHK
(1) The CHK instruction is the instruction used for the bidirectional operation as shown on the following page to confirm the
nature of the system failure.
(a) When the CHK instruction is executed, a failure diagnosis check is conducted with the designated check conditions,
and if a failure is detected, SM80 is turned ON, and the failure number is stored at SD80 as a BCD value.
The error code "9010" will be returned if a failure is detected.
The contact number where the failure was discovered is stored at the upper 3 digits of SD80 (see Page 442,
Section 7.10.1 (3)), and the coil number where the failure was detected (see Page 442, Section 7.10.1 (2)) is stored
at the lower 1 digit of SD80.
Before the detection of failure
440
Command
X
Check condition (Only a contact is valid; b contact is ignored)
Up to 150 contacts can be connected
R, ZR
Word Bit
TO
X0
When T0 is OFF,
program jumps to the
instruction next to the
CHK instruction.
At the detection of failure of
Contact No.: 62, Coil No.: 3
SM80 OFF
SD80 0 0 0 0
High
Basic
performance
X X X
Only input (X) can be used
J \
U \G
Word
––
CHKST
X2
CHK
After the detection of failure
SM80
SD80
Process LCPU
Redundant Universal
CHKST
CHK
Zn Constants
Y10
ON
0 6 2 3
Other