Mitsubishi MELSEC-A Series Programming Manual page 328

7. APPLICATION INSTRUCTIONS
P254
Example Processing is performed as
X is X0, X
2) The internal relay of which number (Y ) is same as the contact number
(X ) of forward stroke end sensors must be controlled as follows.
In forward run: Turn it ON.
In backward run: Turn it OFF.
(2) The CHK instruction executes processing equivalent to the circuit shown below
with one specified contact.
M0
X X
CHK
Max. 150 contact points
+1 is X1 and Y is Y0.
POINT
The CHK instruction performs error check following the circuit pattern
illustrated above. The circuit pattern cannot be changed.
CJ P0
(Both of the forward stroke end and backward
M0 D0
stroke end sensors are actuated in forward run.)
X
Condition 1
(Both of the forward stroke end and backward
stroke end sensors are actuated in forward run.)
X
Condition 2
(Backward run when the forward stroke end
sensor is actuated.)
X
Condition 3
(Forward run when the backward stroke end
sensor is actuated.)
Y
Condition 4
(Forward run when the backward stroke end
sensor is not actuated.)
Y
Condition 5
(Backward run when the forward stroke end
sensor is not actuated.)
X
Condition 6
7 − 126
MELSEC-A
Y
X +1
SET
MOV Error code 1
X +1 Y
SET
MOV
Error code 2
Y
SET
MOV
Error code 3
X +1
SET
MOV
Error code 4
X +1
SET
MOV
Error code 5
Y
SET
MOV
Error code 6
M0
D0
M0
D0
M0
D0
M0
D0
M0
D0
M0
D0