Important Points - Mitsubishi MELSEC-F FX3U Series User Manual

FX /FX Series PLC User's Manual - Positioning Control Edition
3U 3UC
Built-in Positioning Function
6.3.4

Important Points

• If an input (X000 to X007) of the main unit is specified for the near-point input signal specified by
interruption function will be adopted 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 the other device (auxiliary relay, etc.) is specified.
If input relay X010 or below is specified for the near-point signal, the input filter (10 ms) will be adopted.
• If an input (X000 to X007) is specified for the near-point signal
following items:
- High-speed counter
- Input interruption
- Pulse catch
- SPD instruction
- DSZR instruction
- DVIT instruction
• Properly set the DOG so that the near-point signal (DOG) can be kept at the ON status until the speed is
reduced to the creep speed.
This instruction will start speed reduction to the creep speed at the front end of the DOG, and will stop the
operation at the rear end of the DOG. After that, the current value register will 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 low enough.
The zero return instruction will not reduce the speed before stop. For this reason, if the creep speed is not
low enough, the operation may not be stopped at the specified position due to inertia.
• The DOG search function is not adopted for this instruction. For this reason, 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 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 be reduced and
then the operation will be stopped. In this case, "Instruction execution complete" flag (M8029) will not be
turned on.
• While "pulse output monitor" (BUSY/READY) flag is on, the positioning instruction (including PLSR and
PLSY) that uses the same output cannot be executed.
After the instruction activation contact is turned off, if "pulse output monitor" (BUSY/READY) flag is still on,
do not execute the positioning instruction (including PLSR and PLSY instructions) having the same output
number.
• In the following case, "Instruction execution abnormal end" flag (M8329) will be turned on, and execution of
the instruction will be completed.
- If the forward limit flag or the reverse limit flag is turned on, the speed will be reduced and then the
operation will be stopped. In this case, "Instruction execution abnormal end" flag (M8329) will be turned
on when completing execution of the instruction.
- If the limit flag (forward limit flag or reverse limit flag) on the opposite side of the operation direction is
turned on, the speed will be reduced and then the operation will be stopped.
In this case, "Instruction execution abnormal end" flag (M8329) will be turned on when completing
execution of the instruction.
B - 92
→ For the important points of programming, refer to Section 4.7.
→ For details on "Instruction execution abnormal end" flag, refer to Subsection 4.7.4.
6 Mechanical Zero Return (DSZR/ZRN Instruction)
6.3 Zero Return (ZRN Instruction)
, the input cannot be used for the
S
3
, the
S
3