SSD 605C Product Manual - page 126

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

ACCEL LIMIT

HOLD SIGNAL