Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 82)

82 Rockwell Automation Publication 750-RM002B-EN-P - September 2013
Chapter 1 Drive Configuration
Stop Mode
When P370/371 [Stop Mode A/B] is set to 1 “Ramp” and a Stop command is
issued to the drive, the PID loop continues to operate during the decel ramp until
the PID output becomes more than the master reference. When set to 0 “Coast,”
the drive disables PID and performs a normal stop. This bit is active in Trim
mode only.
Anti-Wind Up
When P1065 [PID Cfg] Bit 5 “Anti Windup” is set to 1 “Enabled” the PID loop
automatically prevents the integrator from creating an excessive error that could
cause loop instability. The integrator is automatically controlled without the
need for PID Reset or PID Hold inputs.
Percent Ref
When using Process PID control the output can be selected as percent of the
Speed Reference. This works in Speed trim mode only, not in Torque Trim or
Exclusive mode.
Examples
Percent Ref selected, Speed Reference = 43 Hz, PID Output = 10%, Maximum
Frequency = 130 Hz. 4.3 Hz is added to the final speed reference.
Percent Ref not selected, Speed Reference = 43 Hz, PID Output = 10%,
Maximum Frequency = 130 Hz. 13.0 Hz is added to the final speed reference.
PID Control
P1066 [PID Control] is a set of bits to dynamically enable and disable the
operation of the process PID controller. When this parameter is interactively
written to from a network it must be done through a data link so the values are
not written to EEprom.
PID Enable
The PID loop can be enabled/disabled. The Enabled status of the PID loop
determines when the PID regulator output is part or all of the commanded
speed. The logic evaluated for the PID Enabled status is shown in the following
ladder diagram.