Справочник Пользователя для Mitsubishi Electronics QCPU

7-175

CHKST,CHK

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.10 Debugging an

d failure

 diagn

osis 

instructions

7

.10.1 Special forma

t failure

 checks (

CHKST,C

HK)

Debugging and failure diagnosis instructions

Special format failure checks (CHKST,CHK)

CHKST,CHK

Function

(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.

(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 (3)), and the coil number where the failure was detected (see (2)) is stored at 

the lower 1 digit of SD80.

Setting 

Data

Internal Devices 

R, ZR

J

\

U

\G

Zn

Constants

Other

Bit

Word

Bit

Word

––

––

Universal

Basic

Command

X

X

X

X

CHKST

CHK

Check condition (Only a contact is valid; b contact is ignored)

Up to 150 contacts can be connected

CHKST

CHK

Only input (X) can be used

X0

CHKST

X2

CHK

Y10

TO

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

Before the detection of failure

After the detection of failure

SM80
SD80

OFF

0 0 0 0

SM80
SD80

ON

0 6 2 3