Pid deadband, Pid preload, Pid limits – Rockwell Automation 284E ArmorStart with EtherNet/IP - User Manual User Manual

Page 330: Pid deadband pid preload pid limits

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Rockwell Automation Publication 280E-UM001B-EN-P – July 2012

Appendix D PID Setup

PID Deadband

Parameter 238 (PID Deadband) is used to set a range, in percent, of the PID
Reference that the drive will ignore.

Example

• (PID Deadband) is set to 5.0

• The PID Reference is 25.0%

• The PID Regulator will not act on a PID Error that falls between 20.0 and

30.0%

PID Preload

The value set in Parameter 239 (PID Preload), in Hertz, will be pre-loaded into
the integral component of the PID at any start or enable. This will cause the
drive’s frequency command to initially jump to that preload frequency, and the
PID loop starts regulating from there.

PID Limits

Parameter 230 (PID Trim Hi) and Parameter 231 (PID Trim Lo) are used to
limit the PID output and are only used in trim mode. (PID Trim Hi) sets the
maximum frequency for the PID output in trim mode. (PID Trim Lo) sets the
reverse frequency limit for the PID output in trim mode. Note that when the
PID reaches the Hi or Lo limit, the PID regulator stops integrating so that
windup does not occur.

PID Enabled

Freq Cmd

PID Output

PID Pre-load Value

PID Pre-load Value > 0

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