Mitsubishi Electric MELDAS MDS-B-SVJ2 Series, Specifications And Instruction Manual

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Chapter 5 Adjustment
5-6
5-2-3 Position loop gain
(1) Setting the position loop gain
The position loop gain (SV003:PGN1) is a parameter that determines the trackability to the
command position. 33 is set as a standard. Set the same position loop gain value between
interpolation axes.
When PGN1 is raised, the settling time will be shortened, but a speed loop that has a
responsiveness that can track the position loop gain with increased response will be required. If
the speed loop responsiveness is insufficient, several Hz of vibration or overshooting will occur
during acceleration/deceleration. Vibration or overshooting will also occur when VGN1 is smaller
than the standard value during VIA adjustment, but the vibration that occurs in the position loop
is generally 10Hz or less. (The VIA vibration that occurs is 10 to 20Hz.) When the position control
includes machine resonance points (Position control machine resonance points occur at the
machine end parts, etc.) because of insufficient machine rigidity, the machine will vibrate during
positioning, etc. In either case, lower PGN1 and adjust so vibration does not occur.
If the machine also vibrates due to machine backlash when the motor stops, the vibration can be
suppressed by lowering the PGN1 and smoothly stopping.
If SHG control is used, an equivalently high position loop gain can be maintained while
suppressing these vibrations. To adjust the SHG control, gradually raise the gain from a setting
where 1/2 of a normal control PGN1 where vibration did not occur was set in PGN1. If the PGN1
setting value is more than 1/2 of the normal control PGN1 when SHG control is used, there is an
improvement effect in position control. (Note that for the settling time the improvement effect is at
1/
2 or more.)
No. Abbrev. Parameter name Explanation Setting range
SV003 PGN1 Position loop gain 1 Set 33 as a standard. If PGN1 is increased, the settling time will be
shortened, but a sufficient speed loop response will be required.
1 ~ 200
SV004 PGN2 Position loop gain 2 Set 0. (For SHG control) 0 ~ 999
SV057 SHGC SHG control gain Set 0. (For SHG control) 0 ~ 999
CAUTION
Always set the same value3 for position loop gain between interpolation axes.
(2) Setting the position loop gain for spindle synchronous control
During spindle synchronous control (synchronous tapping control, etc.), there are three sets of
position loop gain parameters besides the normal control.
No. Abbrev. Parameter name Explanation Setting range
SV049 PGN1sp Position loop gain 1
in spindle
synchronous control
Set 15 as a standard. 1 ~ 200
SV050 PGN2sp Position loop gain 2
in spindle
synchronous control
Set 0 as a standard.
(For SHG control)
0 ~ 999
SV058 SHGCsp SHG control gain in
spindle synchronous
control
Set 0 as a standard.
(For SHG control)
Set the same parameter as the
position loop gain for the spindle
synchronous control.
0 ~ 999
CAUTION
Always set the same value for the position loop gain between the spindle and
servo synchronous axes.