Allen-Bradley PowerFlex 70 Reference Manual page 34

Analog Outputs
34
Filtering
Software filtering will be performed on the analog outputs for certain signal
sources, as specified in Table
described later in this section. Any software filtering is in addition to any
hardware filtering and sampling delays.
Table 1 Software Filters
Quantity Filter
Output Frequency No extra filtering
Commanded Frequency No extra filtering
Output Current Filter A
Output Torque Current Filter A
Output Flux Current Filter A
Output Power Filter A
Output Voltage No extra filtering
DC Bus Voltage Filter A
PI Reference No extra filtering
PI Feedback No extra filtering
PI Error No extra filtering
PI Output No extra filtering
Analog output software filters are specified in terms of the time it will take the
output of the filter to move from 0% to various higher levels, given an
instantaneous step in the filter input from 0% to 100%. The numbers describing
filters in this document should be considered approximate; the actual values will
depend on implementation.
Filter A is a single pole digital filter with a 162ms time constant. Given a 0% to
100% step input from a steady state, the output of Filter A will take 500ms to get
to 95% of maximum, 810 ms to get to 99%, and 910 ms to get to 100%.
PowerFlex 700 Firmware 3.001 (& later) Enhancements
Certain analog output enhancements have been included in firmware version
3.001 (and later) for the PowerFlex 700 Vector Control drive. These include:
• Ability to scale the analog outputs
• Connect scale blocks to the analog outputs
• Analog Output controlled via Datalink
Output Scaling
A new scaling feature has been added to allow scaling. Prior to this feature,
[Analog Outx Lo] and [Analog Outx Hi] limited only the voltage. This voltage
range was scaled to the selected option range listed in [Analog Outx Sel]. With
the new feature, [Analog Outx Lo] and [Analog Outx Hi] still set the voltage
range, but the scaling parameter now scales the range of the [Analog Outx Sel]
selection. See the following example.
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
1. "Filter A" is one possible such filter, and it is