12 - 5
MELSEC-Q
12 CONTROL SUB FUNCTIONS
(2) OPR retry operation when the workpiece is outsi de the range between the
upper and lower limits.
1) When the direction from the workpiece to the OP is the same as the " Pr.44 OPR direction", a
normal machine OPR is carried out.
Pr. 44 OPR direction
Upper limit
Lower limit
Movement range
Machine OPR start OP
Zero signal
Near-point dog
2) When the direction from the workpiece to the OP is the opposite direction f rom the " Pr.44 OPR
direction", the operation carries out a deceleration stop when th e ne a r-p oint dog tu rn s OFF, and
then carries out a machine OPR in the directio n set in " Pr.44 OPR direction".
Pr. 44 OPR direction
Near-point dog
Upper limit
Lower limit
Movement range
Machine OPR start
OP
Zero signal
Note) The above figures (a) and (b) are examples where " Pr.44 OPR direct ion" is set to "0: Positive
direction". When "0: Positive direction" is set in Pr.44 , check that the limit switch placed in the
OPR direction acts as the upper limit. When "1: Negative directio n" is set in Pr.44 , check that
the limit switch placed in the OPR direction acts as the lower limit. Incorrect wiring of these lim it
switches may cause improper OPR retry operat ion. If any malfunction is identified, chec k and
correct " Pr.6 Rotation direction settin g" and the wiring.
Fig. 12.2 OPR retry operation from on limit (lim it switch OFF)