Speed Reference - Allen-Bradley PowerFlex Reference Manual

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Speed Reference

Speed Reference
Speed Reference Scaling
[Speed Ref A, B Sel]
[TB Man Ref Sel]
The reference generation function is to provide a reference to the drive. Its
purpose is to determine which reference source should be used based on
parameters and logic command. Seven references can be selected by logic
command. The first two references (A & B) have selectable sources.
References A & B can be trimmed by a trim that has selectable sources. The
other five are fixed at preset frequencies three to seven. The user will be able
to select if the reference is unipolar, which is limited to a positive value and
enables the direction bit or bipolar which disables the direction bit allowing
the reference sign to command direction. The min and max speed limit the
final reference going to the skip band module.
Seven references can be selected through logic command.
Logic command (drive control command) is a bit enumerated parameter,
which contains the final command after it has been funneled through a
command evaluation module of masks, owners, and transitions. Logic
commands come from the terminal block, DPI peripherals, and HIM all at
the same time. Logic command could consists of stop, start, jog, accel ,
decel ,MOP inc/dec, direction, etc. The command evaluation module is not
within the scope of this document and will be covered in another document.
The first two references are programmable. The user can select which
source they would like for each reference. If an analog input reference or
pulse input reference (PowerFlex 700 Only) is chosen, two scale parameters
are provide to scale the reference. The scale min/max are based on other
parameter (uni/bipolar, analog in config, etc.). See also
more information.
The last five are fixed references, preset frequencies 3-7.
Reference A & B can be trimmed with a selectable source trim. If an analog
input reference or pulse input reference (PowerFlex 700 Only) is chosen,
two scale parameters are provide to scale the reference. The trim is a +/–
reference which can be set to trim none, A, B, or Both.
Auto / Manual
Many applications require a "manual mode" where adjustments can be
made and setup can be done by offering local control of the drive speed.
Typically, these adjustments could be made via a "local" HIM mounted on
the drive. When all setup is complete, control of the drive frequency
command is turned over to automatic control from a remote source such as
a PLC. Also see Auto / Manual on page
Analog Inputs
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