Rockwell Automation 20B PowerFlex 700 Custom Firmware - Option AE - Manual (Page 2)

2 PowerFlex
 700VC Custom Firmware
• When Dig Out 1 is energized to start the first fixed speed fan/pump
the drive automatically performs the following steps to handle the
transition from drive only to drive plus a fixed speed fan/pump:
– [Preset Speed 1] is set to [Dig Out1 OffLevel] + 2 Hz (this sets a
target frequency in the lower portion of the frequency range
defined for the first fixed speed fan/pump).
– The PI regulator is automatically disabled (by clearing the “PI
Enable” bit of [PI Control] causing [Speed Ref Source] to switch
from “PI Output” to the source selected by the reference
selection logic of the drive) so the drive will follow an open loop
speed command while the fixed speed fan/pump is started. This
will cause the drive output to ramp down to [Preset Speed 1]
following the selected decel rate (see [Decel Time 1/2]).
Important: For proper operation the reference select logic must
be configured to select “Preset Spd 1" as the [Speed
Ref Source] when the PI regulator is disabled.
– When the drive reaches the commanded frequency or the error
signal of the PI regulator becomes positive, the drive will
re-enable the PI regulator (by setting the “PI Enable” bit of [PI
Control]) so the process variable is again regulated by the drive.
Important: The same control is used when the second fixed
speed fan/pump is started with Dig Out 3, except the
frequency target is based on [Dig Out3 OffLevel].
• When a fixed speed fan/pump is stopped the PI regulator will control
the response of the drive to the change in the process variable.
Example
Fan #1 starts when the drive frequency exceeds 40 Hz and stops when the drive frequency
drops below 19 Hz. Fan #2 starts when the drive frequency exceeds 59 Hz and stops when
the drive drops below 25 Hz. The following configuration would be used:
New Parameters
New parameters for this custom firmware are shown in bold in the
following figure. Patrameter descriptions follow. Note that the Advanced
Parameter View is shown (parameter 196 [Param Access Lvl] set to “1,
Advanced”). Some parameters will not be shown if the Basic Parameter
View is selected.
Parameter Setting
[Dig Out1 Sel] “58, Fan & Pump Ctrl”
[Dig Out1 OnLevel] “40 Hz”
[Dig Out1 OffLevel] “19 Hz”
[Dig Out3 Sel] “58, Fan & Pump Ctrl”
[Dig Out3 OnLevel] “59 Hz”
[Dig Out3 OffLevel] “25 Hz”
[Speed Ref A Sel] “Preset Spd 1”