Low Current Threshold; Brake Apply Speed; Brake Apply Speed Delay; Brake-Apply Delay - Emerson unidrive sp User Manual

Parameter Keypad and
Menu 12
structure display

Low current threshold

12.43
Drive modes Open-loop, Closed-loop vector, Servo
Coding Bit SP
Range Open-loop, Closed-loop vector, Servo
Default Open-loop, Closed-loop vector, Servo
Update rate Background read
If the current magnitude falls below the lower current threshold the brake is applied immediately. The lower threshold should be set to the required
level to detect the condition where the motor has been disconnected from the drive. If this parameter is set to zero the loss of current will not cause
the brake to be applied. However, the flux detection and current threshold latch will be reset when the drive is disabled.
12.45

Brake apply speed

Drive modes Closed-loop vector, Servo
Coding Bit SP
Range Closed-loop vector, Servo
Default Closed-loop vector, Servo
Update rate Background read
When stopping, the drive reference can be removed (i.e. Pr 1.11 = 0), but the brake will remain energized (open) until the motor has remained at a
speed below the brake apply speed for the delay defined by Pr 12.46. The delay prevents rapid activation and de-activation of the brake when fine
control of a motor is required close to zero speed.

Brake apply speed delay

12.46
Drive modes Closed-loop vector, Servo
Coding Bit SP
Range Closed-loop vector, Servo
Default Closed-loop vector, Servo
Update rate Background read
See Pr 12.45.
12.47 Post-brake release delay
Drive modes Closed-loop vector, Servo
Coding Bit SP
Range Closed-loop vector, Servo
Default Closed-loop vector, Servo
Update rate Background read
The post-brake release time is used to allow for the brake release time. From the time that the drive is enabled and then during this period the speed
reference is held constant at zero, so that there is no sudden increase in motor speed when the brake actually releases.

Brake-apply delay

12.48
Drive modes Closed-loop vector, Servo
Coding Bit SP
Range Closed-loop vector, Servo
Default Closed-loop vector, Servo
Update rate Background read
The brake apply delay is used to allow for the brake application time. During this period the Hold zero speed parameter (Pr 6.08) is one, and so the
drive is enabled with zero speed reference. This ensures that the motor remains stationary while the brake is being applied.
230
Parameter Parameter
x.00 description format
FI DE Txt VM DP ND
0 to 200 %
10
FI DE Txt VM DP ND
0 to 200 rpm
5
FI DE Txt VM DP ND
1
0.0 to 25.0 s
1.0
FI DE Txt VM DP ND
1
0.0 to 25.0 s
1.0
FI DE Txt VM DP ND
1
0.0 to 25.0 s
1.0
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Advanced parameter
Macros
descriptions
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
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
Serial comms Electronic
Performance RFC mode
protocol nameplate
PS
1
PS
1
PS
1
PS
1
PS
Unidrive SP Advanced User Guide
Issue Number: 10