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8.4.12 Precautions When Changing Speed (Common to F171 and F172)
Precautions during programming
- To change the speed, specify the execution condition of instruction to be always executed.
- Using the type 0 of trapezoidal control instruction (F171) enables to perform the
acceleration/deceleration control up to the target value. Using the type 1 of trapezoidal control
instruction (F171) enables to perform the acceleration/deceleration control up to the maximum speed
(50 kHz).
- The speed cannot be changed during the deceleration requested by the deceleration stop and during
the deceleration to stop at the target position.
- Acceleration cannot be performed from that position when the elapsed value goes beyond the
acceleration forbidden area starting position. The acceleration forbidden area starting position can be
monitored by the special data registers shown in the table below.
- The speed cannot be changed to a value below the deceleration minimum speed. If a value below the
deceleration minimum speed is specified, the speed will be corrected. The deceleration minimum
speed can be monitored by the special data registers shown in the table below.
Pulse output control area
Channel No. Deceleration minimum speed area
Acceleration forbidden area
CH2 DT90427 DT90428 to DT90429