Programming
Page
D-154
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
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SPEED LOOP
SETUP::MOTOR CONTROL::SPEED LOOP
Designed for SENSORLESS VEC and CLOSED-LOOP VEC Motor Control Modes.
This function block controls the speed of the motor by comparing the actual speed to the demanded speed, and applying more
or less torque in response to the error.
Fixed Inputs and Outputs
These parameters are not viewable on the keypad, They are accessible using the DSE 890 Configuration Tool.
Speed Demand
This is connected to the output of the REFERENCE function block.
Speed Feedback
The speed feedback is derived from the encoder when the Control Mode is configured as CLOSED-LOOP VEC. When
configured as SENSORLESS VEC the speed feedback is calculated from the voltages and currents slowing in the motor, and
the motor model.
Torque Demand
The output of the SPEED LOOP function block is a torque demand. This torque demand is passed on to the TORQUE LIMIT
function block.
Parameter Descriptions
SPEED PROP GAIN
PREF: 78.01
Default: 20.0
Range: 0.0 to 3000.0
Sets the proportional gain of the loop.
Speed error (revolutions per second) x proportional gain = torque percent.
SPEED INT TIME
PREF: 78.02
Default: 100 ms
Range: 1 to 15000 ms
This is the integral time constant of the speed loop. A speed error which causes the proportional term to produce a torque
demand T, will cause the integral term to also ramp up to a torque demand T after a time equal to “speed int time”.
