Hold Zero Speed; Catch A Spinning Motor; Enable Stop Key - Control Techniques unidrive sp Advanced User's Manual

Parameter Keypad and Parameter
structure display x.00
6.08

Hold zero speed

Drive modes Open-loop, Closed-loop vector, Servo
Bit SP FI
Coding
1
Open-loop, Closed-loop vector
Default
Servo
Update rate 4ms read
When this bit is set the drive remains active even when the run command has been removed and the motor has reached standstill. The drive goes to
the 'StoP' state instead of the 'rdy' state.
6.09

Catch a spinning motor

Drive modes Open-loop, Closed-loop vector, Servo
Bit SP FI
Coding
Open-loop
Range
Closed-loop vector, Servo
Open-loop
Default
Closed-loop vector, Servo
Update rate Background read
Open-loop
When the drive is enabled with this parameter at zero, the output frequency starts at zero and ramps to the required reference. When the drive is
enabled with this parameter at a non-zero value, the drive performs a start-up test to determine the motor speed and then sets the initial output
frequency to the synchronous frequency of the motor. The test is not carried out, and the motor frequency starts at zero, if the run command is given
when the drive is in the stop state, or when the drive is first enabled after power-up with Ur_I voltage mode, or when the run command is given with
Ur_S voltage mode. With default parameters the length of the test is approximately 250ms, however, if the motor has a long rotor time constant
(usually large motors) it may be necessary to extend the test time. The drive will do this automatically if the motor parameters including the rated load
rpm are set up correctly for the motor.
For the test to operate correctly it is important that the stator resistance (Pr 5.17, Pr 21.12) is set up correctly. This applies even if fixed boost (Fd) or
square law (SrE) voltage mode is being used. The test uses the rated magnetising current of the motor during the test, therefore the rated current (Pr
5.07, Pr 21.07 and Pr 5.10, Pr 21.10) and power factor should be set to values close to those of the motor, although these parameters are not as
critical as the stator resistance.
It should be noted that a stationary lightly loaded motor with low inertia may move slightly during the test. The direction of the movement is undefined.
Restrictions may be placed on the direction of this movement and on the frequencies detected by the drive as follows:
Pr 6.09 Function
0 Disabled
1 Detect all frequencies
2 Detect positive frequencies only
3 Detect negative frequencies only
Closed-loop vector and Servo
When the drive is enabled with this bit at zero, the post ramp reference (Pr 2.01) starts at zero and ramps to the required reference. When the drive is
enabled with this parameter at one, the post ramp reference is set to the motor speed.
6.12

Enable stop key

Drive modes Open-loop, Closed-loop vector, Servo
Bit SP FI
Coding
1
Default Open-loop, Closed-loop vector, Servo
Update rate Background read
This parameter permanently enables the Stop key on the drive such that the drive will always stop when the Stop key is pressed. If keypad mode is
selected this has no effect because the Stop key is automatically enabled.
The sequencer logic has been designed so that pressing the Stop key, whether the Stop key is enabled or not, does not make the drive change from
a stopped to a running condition. As the Stop key is also used to reset trips this means that if the Stop key is pressed when the drive is tripped, the trip
will be reset, but the drive does not start. This is done as follows.
Unidrive SP Advanced User Guide
Issue Number: 7
Parameter Advanced parameter
description format descriptions
DE TE VM DP ND RA
0
1
DE TE VM DP ND RA
3
1
0
1
DE TE VM DP ND RA
0
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Serial comms Electronic
Macros
protocol nameplate
NC NV PT US RW BU
1 1
NC NV PT US RW BU
1 1 1
NC NV PT US RW BU
1 1
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