Rockwell Automation SP600 User Manual Version 3.0 - Manual (Page 132)

11-30 SP600 AC Drive User Manual
• Enabled = Initializes the PI integrator to the commanded
speed while the PI is disabled.
• Disabled = The PI integrator is loaded with the PI Pre-load
(133) while the PI is disabled.
Bit 3 - Ramp Ref
• Enables/disables ramping the PI reference using PI
Feedback as the starting point and ramping to the selected
PI Reference after PI is enabled. The active accel time is
used for the PI ramp reference slew rate. The ramping is
bypassed when the reference equals the setpoint. The ramp
used is set by the active ramps (parameters 140 to 143).
Bit 4 - Zero Clamp
• Enables/disables option to limit operation so that the output
frequency at the PI regulator always has the same sign as
the master speed reference. This limits the possible drive
action to one direction only. Output from the drive will be from
zero to maximum frequency forward or zero to maximum
frequency reverse.
Bit 5 - Feedback Sqrt (Square Root Feedback)
• Enables/disables the option of using the square root of the
feedback signal as the PI feedback. This is used for pressure
control because fans and pumps vary pressure with the
square of the speed.
Bit 6 - Stop Mode
• When enabled, and a stop command is issued to the drive,
the PI loop will continue to operate during the decel ramp.
When disabled, the drive will perform a normal stop.
Bit 7 - Anti Wind Up
• When enabled, the PI loop will automatically prevent the
integrator from creating an excessive error that could cause
instability. The integrator will be controlled without the need
for PI Reset or PI Hold inputs.
Controls the PI regulator. You can use a Datalink parameter or an
assigned digital input to write to this parameter.
PI control allows the drive to take a reference signal (setpoint) and
an actual signal (feedback) and automatically adjust the speed of
the drive to match the actual signal to the reference.
125 PI Control
Range: See figure 11.11
Default: See figure 11.11
Access: 2 Path: Speed Command>Process PI
See also: 80, 124-138