Control Techniques Digitax ST Advanced User's Manual page 86

Parameter
Menu 5
structure
5.31 Voltage controller gain
Bit SP
Coding
Range 0 to 30
Default 1
Update rate Background read
This parameter controls the gain of the voltage controller used for mains loss and standard ramp control. If the parameter is set to 1 the gain used is
suitable for applications where the drive is used alone. Higher values are intended for applications where the DC bus of each drive is connected in
parallel and the drive is used as a master for mains loss control (If motors are locked together using digital-locking, using a master for mains loss
control, it is unlikely that the system will be stable during mains loss unless the power rating of the master is much higher than the combined rating of
the slaves. This is due to the lag created by the master motor inertia).
5.32 Motor torque per amp (Kt)
Bit SP
Coding
Range
0.00 to 500.00 NmA
Default 1.60
Update rate Background (1s) read
This parameter shows the motor torque per amp of active (torque producing) current used to calculate the speed controller gains when the automatic
set-up methods are active (i.e. Pr 3.17 = 1 or 2).
The motor torque per amp (Kt) must be entered in this parameter by the user for the automatic gain calculation system to operate correctly, and to
allow the drive to calculate the correct inertia during and inertia autotune.
5.33 Motor volts per 1000rpm (Ke)
Bit SP
Coding
Range 0 to 10,000
Default 98
Second motor
Pr 21.30
parameter
Background read
Update rate
This parameter is used to set up the current controller integral terms when the drive is disabled to prevent current transients when the drive is enabled
with a spinning motor. It is also used to provide a voltage feed forward term if high dynamic performance is selected with Pr 5.26.
5.35 Disable auto-switching frequency change
Bit SP
Coding
1
Default 0
Background read
Update rate
The drive thermal protection scheme (see Pr 7.34 on page 106) reduces the switching frequency automatically when necessary to prevent the drive
from overheating. It is possible to disable this feature by setting this bit parameter to one. If the feature is disabled the drive trips immediately when
the IGBT temperature is too high.
5.36 Motor pole pitch
Bit SP
Coding
Range 0 to 655.35mm
Default 0.00mm
Second motor
Pr 21.31
parameter
Background read
Update rate
This parameter should be set up to give the pole pitch of a linear motor, i.e. the movement of the motor for one cycle of the drive power output
waveforms, if auto-configuration with a linear EnDat encoder is required.
86
Keypad and
Parameter x.00
display
FI DE Txt VM DP ND RA
FI DE TE VM DP ND RA NC NV
2
-1
FI DE Txt VM DP ND
FI DE Txt VM DP ND
FI DE TE VM DP ND
2
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Parameter Advanced parameter
description format descriptions
NC NV PT US RW BU
1 1
PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
Serial comms Electronic
protocol nameplate
PS
1
PS
1
PS
1
PS
PS
1
Digitax ST Advanced User Guide
Performance
Issue Number: 1