Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 101)

Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013 101
Detail Drive Configuration and Operation Chapter 1
Settings for parameter 381 [PreChrg Err Cnfg]:
“0 “Ignore”: This disables the precharge timeout fault. With this setting the drive
ignores condition 3 above so that the drive does not check for an unstable bus
voltage. Then after the precharge timeout period the precharge control will
complete precharge providing all of the other conditions for precharge are met.
This feature could be useful in cases where bus disturbances are created by
another drive in a common or shared bus installation.
“1 “Alarm”: If the precharge does not complete within the timeout period, the
drive does not fault, but it sets an alarm bit in parameter 326 [Alarm Status 1] bit
30 “Precharge Er”.
“2 “FltCoastStop”: This is the factory default setting. If the precharge does not
complete within the timeout period, the drive faults and disables the PWM
output.
External Precharge
In cases where the user must provide external drive precharge hardware and
control, the user should consider the current limit necessary to protect the drive
and fuses, the breaking capability of the precharge device, the regenerative
capability of the drive/system, whether or not ride through control will be
accommodated, impedance isolation that may be needed between drives, braking
requirements and sharing between drives and the power disconnect operation in
a system. The drive's precharge and ride through functions will still run even
though the actual precharge hardware is not controlled by the drive. The drive's
enable (parameter 155 [Logic Status], bit 0 “Enabled”), precharge enable
(controlled with a digital input or parameter 411 [PreChrg Control]) and
precharge done (parameter 555 [MC Status] bit 11 “PreChrg Done”) parameters
are available for the external precharge/ride through control in cases where the
users would like to provide coordinated operation between the external
precharge and the drive's ride through operation.
Precharge Staging
Parameter 472 [PreCharge Delay] can be used in conjunction with precharge
enable (see 1 above) to coordinate the precharge operation of a group of drives.
Typical uses may include common bus or shared bus applications. The precharge
coordination can be open loop, using different precharge delay times or could be
closed loop by monitoring the precharge done status (parameter 555 bit 11) of
each drive before the next drive in the sequence is enabled for precharge. The
maximum value for PreCharge Delay is limited by parameter 410 [PreChrg
Timeout]. The maximum value for [Precharge Delay] is determined by the
following calculation:
[Precharge Delay] Max = [PreChrg Timeout] - 1.