Characteristics Improvement; Optimal Adjustment Of Cycle Time; Position Loop Gain - Mitsubishi MELDAS HS Series Specifications And Instruction Manual

8-3 Characteristics improvement

8-3-1 Optimal adjustment of cycle time

The following items must be adjusted to adjust the cycle time. Refer to the Instruction Manuals
provided with each CNC for the acceleration/deceleration pattern.
1) Rapid traverse rate (rapid)
2) Clamp speed (clamp)
3) Acceleration/deceleration time : Set the time to reach the feedrate.
constant (G0t∗, G1t∗)
4) In-position width (SV024)
5) Position loop gain (SV003)
(1) Adjusting the rapid traverse rate
To adjust the rapid traverse, the CNC axis specification parameter rapid traverse rate (rapid) and
acceleration/deceleration time constant (G0t∗) are adjusted. The rapid traverse rate is set so that
the motor speed matches the machine specifications in the range below the maximum speed in
the motor specifications. For the acceleration/deceleration time constants, carry out rapid
traverse reciprocation operation, and set so that the maximum current command value at
acceleration/deceleration is within the range shown below. (Only when the rapid traverse rate is
below the rated speed.) Set the same value as the adjusted acceleration/deceleration time
constant in the servo parameter's deceleration control time constant (SV056: EMGt). (When
deceleration control is set.)
For motors in which the maximum speed is greater than the rated speed, the output torque is
particularly restricted in the region at or above the rated speed. When adjusting, watch the
current FB waveform during acceleration/deceleration, and adjust so that the torque is within the
specified range. Be careful, as insufficient torque can easily occur when the amplifier input
voltage is low (170 to 190V), and an excessive error can easily occur during
acceleration/deceleration.
HS-MF Series
Motor type
HS-MF23
(2) Adjusting the cutting rate
To adjust the cutting rate, the CNC axis specification parameter clamp speed (clamp) and
acceleration/deceleration time constant (G1t∗) are adjusted. The in-position width at this time
must be set to the same value as actual cutting.
• Determining the clamp rate and adjusting the acceleration/deceleration time constant
(Features)
(Adjustment) Carry out cutting feed reciprocation operation with no dwell at the maximum
• Setting the step acceleration/deceleration and adjusting the clamp speed
(Features)
(Adjustment) Set 1 (step) for the acceleration/deceleration time constant and carry out
Chapter 8 Adjustment
: This will affect the maximum speed during positioning.
: This will affect the maximum speed during cutting.
: This will affect each block's movement command end time.
: This will affect each block's movement command settling time.
Max. current
Motor type
command value
280 to 320% HS-RF43
HS-RF73
The maximum cutting rate (clamp speed) can be determined freely.
cutting rate and adjust the acceleration/deceleration time constant so that the
maximum current command value during acceleration/deceleration is within the
range shown below.
The acceleration/deceleration time constant is determined with the position
loop in the servo, so the acceleration/deceleration F ⊿T can be reduced.
cutting feed reciprocation operation with no dwell. Adjust the cutting feed rate
so that the maximum current command value during acceleration/deceleration
is within the range shown below, and then set the value in the clamp speed.
HS-RF Series
Max. current
command value
200 to 240%
200 to 240%
8–10
HS-SF Series
Max. current
Motor type
command value
HS-SF52 420 to 470%
HS-SF53 420 to 470%
HS-SF102 440 to 500%
HS-SF103 500 to 560%
HS-SF202 420 to 470%