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PLC User's Manual - Positioning Control Edition
Built-in Positioning Functions
4 Before Programming
4.3 Various Special Relays for Operation Commands
B - 50
2. Zero return instruction (ZRN instruction)
Zero return will be performed in the reverse rotation direction only.
(During zero return, the value indicated by the current value register will be decreased.)
To perform zero return in the forward rotation direction using the ZRN instruction (zero return instruction):
To perform zero return in the forward rotation direction, create a program to control the output (Y) relay set as
a "rotational direction signal" as follows:
→ For details on programming, refer to Section 4.7.
→ To use
the
main unit (transistor output), refer to Section 4.8.
→ To use a high-speed output special adapter, refer to Section 4.9.
1) Turn on Y (rotational direction signal).
2) Refresh Y output using the REF (FNC50) instruction.
3) Execute the ZRN instruction (zero return instruction).
4) Using the execution completion flag (M8029) of the ZRN instruction (zero return instruction), reset
Y (rotational direction signal).
Example program:
The following program uses Y004 as the rotational direction signal for Y000.
C
omman
d
input
Turns on (sets) Y004 as the
rotational direction signal of Y000
(pulse output destination).
M8340
Y000 output
pulse monitor
K8Y000
Y000
Y004RST
Refreshes Y000 to Y007.
Executes ZRN instruction.
Resets the rotational direction
signal (Y004) using the instruction
execution complete flag.
Y004SET
FNC 50
REFP
FNC156
DZRN
S
1
•
S
2
•
S
3
•
M8029
M11RST
M10RST
M10SET
Origin data reading completion flag
Resets the rotational direction signal
(Y004) using the instruction
execution abnormal end flag.
Y004RST
M8329
M11SET
Abnormal end of zero return
a)
b)
c)
d)