Filter
Top Products
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Positioning Control Edition
Built-in Positioning Functions
6 Mechanical Zero Return (DSZR/ZRN Instruction)
6.3 Zero Return (ZRN Instruction)
B - 106
6.3.4 Important Points
→ For important programming points, refer to Section 4.7.
• If an input (X000 to X007) of the main unit is specified for the near-point input signal specified by , the
PLC interruption function will be used to stop the operation.
Under the following condition, however, operation may be affected by the input constant or the scan time of
the sequence program.
- An input number of X010 or below (or other device (auxiliary relay, etc.)) is specified.
If input relay X010 or higher is specified for the near-point signal, the input filter (10 ms) will be applied.
• If an input (X000 to X007) is specified for the near-point signal , the input cannot be used for the
following items:
- High-speed counter
- Input interruption
- Pulse catch
- SPD instruction
- DSZR instruction
- DVIT instruction
*1
• Properly set the DOG so that the near-point signal (DOG) can be kept ON until the speed is reduced to the
creep speed.
This instruction will start speed reduction at the front end of the DOG, and will stop the operation at the rear
end of the DOG. The current value register will then be cleared (reset to "0").
If the speed is not reduced to the creep speed before detecting the rear end of the DOG, the operation may
not be stopped at the specified position.
• The creep speed should be slow enough.
The zero return instruction will not decelerate at the stop point. Therefore, if the creep speed is not slow
enough, the operation may not stop at the specified position due to inertia.
• The DOG search function does not apply for this instruction. Therefore, start the zero return operation on
the front side of the near-point signal. If it is necessary to use the DOG search function, use the DSZR
instruction.
• The zero-phase signal of the servo motor cannot be used. For this reason, if fine adjustment of the origin
position is needed, adjust the position of the near-point signal (DOG).
• If the instruction activation contact is turned off during zero return operation, the speed will decelerate and
the operation will stop. In this case, the "Instruction execution complete" flag (M8029) will not turn on.
• While the "pulse output monitor" (BUSY/READY) flag is on, a positioning instruction (including PLSR and
PLSY) that uses the same output cannot be executed.
If the "pulse output monitor" (BUSY/READY) flag is still on after the instruction activation contact is turned
off, do not execute a positioning instruction (including PLSR and PLSY instructions) that uses the same
output number.
• In the following case, the "Instruction execution abnormal end" flag (M8329) will be turned on, and
execution of the instruction will be completed.
→ For details on the "Instruction execution abnormal end" flag, refer to Subsection 4.7.4.
- If the forward limit relay or the reverse limit relay is turned on, the speed will decelerate and the
operation will stop. In this case, the "Instruction execution abnormal end" flag (M8329) will be turned on
when execution of the instruction is complete.
- If the limit relay (forward limit relay or reverse limit relay) on the opposite side of the operation direction
is turned on, the speed will decelerate and the operation will stop.
In this case, the "Instruction execution abnormal end" flag (M8329) will be turned on when execution of
the instruction is complete.
*1. Only available for
FX
3U
and
FX
3UC
PLCs.
S
3
S
3