442
CHKST, CHK
(2) Depending on the designated contact, the CHK instruction undergoes processing identical to that shown for the ladder
below:
(3) Numbers 1 to 150 from the vertical bus on the left side have been allocated as contact numbers during failure detection.
(4) Reset SM80 and SD80 prior to forcing the execution of the CHK instruction.
After the execution of the CHK instruction, it cannot be performed once again until SM80 and SD80 have been reset.
(The contents of SM80 and SD80 will be preserved until reset by user.)
(5) A CHKST instruction must be placed before the CHK instruction.
An error will be returned if an instruction other than the LD, LDI, AND or ANI instruction is used between the CHK
instruction and the CHKST instruction.
(Error code: 4235)
(6) The CHK instruction can be written at any step of the program.
However, there is a limit in the number of uses of the CHK instruction.
• Can be used up to two places in all program files being executed.
• Can be used only one place in a single program file.
An error will be returned if the CHK instruction is used exceeding the number of uses specified above.
(Error code: 4235)
SM80
SET
MOV Failure No. 6 SD80
Y
X
Coil No. 6
CHK
CHKST
TO
SM80
X
X
X +1 Y
X +1 Y
SM80
SET
SET
MOV Failure No. 1 SD80
MOV Failure No. 2 SD80
SM80
SET
MOV Failure No. 3 SD80
X
Y
(Detection by both ad
v
ance and retraction end sensors
during ad
v
ance operation of the con
v
eyor)
(Detection by both ad
v
ance and retraction end sensors
during retract operation of the con
v
eyor)
(Ad
v
ance operation of the con
v
eyor at the detection
by the ad
v
ance end sensor)
SM80
SET
MOV Failure No. 4 SD80
Y
X +1
(Retract operation of the con
v
eyor at the detection
by the retraction end sensor)
SM80
SET
MOV Failure No. 5 SD80
Y
X +1
(Ad
v
ance operation of the con
v
eyor during no detection
by the retraction end sensor)
(Retract operation of the con
v
eyer at the detection
by the ad
v
ance end sensor)
Coil No. 1
Coil No. 2
Coil No. 3
Coil No. 4
Coil No. 5
Max. 150 contacts
Example
X
X0
X
X
1
X
+ 1
Y
Y
0
X
Executes the same processing
as the ladder indicated abo
v
e
C
HK
X5
X7
X9
1
4
9
150
1
2
3
Contact
N
o
.
X1A
X1C