SSD 605C - Slew Rate Limit

6-60 Programming Your Application
605C Frequency Inverter
SLEW RATE LIMIT
This function block prevents over-current
and over-voltage faults occurring due to a
rapidly changing setpoint.
Functional Description
The slew rate limits block obtains the setpoint from the output of the application, correctly
scaled by the setpoint scale block. The rate of change limits are then applied and the setpoint is
then passed on for future processing by the current limit block.
When the braking block determines that the internal dc link voltage is too high it issues a Hold
signal. This causes the slew rate limits block to hold the setpoint at its current value. This
typically lasts for only 1ms, time for the excess energy to be dumped into the braking resistor.
MMI Menu Map
1
SETUP PARAMETERS
2
FUNCTION BLOCKS
3
MOTOR CONTROL
4
SLEW RATE LIMIT
SLEW ENABLE
SLEW ACCEL LIMIT
SLEW DECEL LIMIT
SLEW RATE LIMIT
TRUE – [ 60] ENABLE
–
500.0 Hz/s
–
[ 62] ACCEL LIMIT
–
500.0 Hz/s
–
[ 61] DECEL LIMIT
–
Parameter Descriptions
ENABLE
Range: FALSE / TRUE
When this parameter is FALSE, this function block is disabled and the setpoint is unaffected by
this function block.
ACCEL LIMIT
Range: 12.0 to 1200.0 Hz/s
The maximum rate at which the setpoint may accelerate away from zero.
DECEL LIMIT
Range: 12.0 to 1200.0 Hz/s
The maximum rate at which the setpoint may decelerate towards zero.
SETPOINT
DECEL LIMIT
A
CCEL LIMIT
HOLD SIGNAL