Power Brick Controller User Manual
Manual Motor Setup
137
Automatic Stepper Phasing
The automatic Stepper phasing technique is one of two phase referencing routines built-into the Power
PMAC firmware (the other one is the four-guess technique, not discussed here). The automatic stepper
method can be used with any type of feedback device. It is simple to set up and can establish a very accurate
phase reference.
Without the presence of digital hall sensors or an absolute encoder, the automatic stepper method can be
saved and used in the power-up routine of the motor. Prior to implementing it permanently, it is highly
recommended to test the automatic stepper method for consistency at random locations of the travel. Setting
up the automatic stepper phasing technique requires configuring the following motor structure elements:
Motor[].PhaseFindingDac
specifies the magnitude of the output (current) used in the search
move.
Motor[].I2Tset / 2
is a "good" conservative value to start with.
Motor[].PhaseFindingTime
specifies the amount of time (in real time interrupts) allowed for the
search move. This can be computed in milliseconds, per the example equation below.
Motor[].AbsPhasePosOffset
specifies the minimum motion that qualifies the search as being a
valid search. Typically set to 1/5
th
of a commutation cycle (2048 / 5).
Motor[].PowerOnMode
specifies whether a search move is applied on power-up. This is not
advised with the automatic stepper phasing since the main bus power may not be available when
the PMAC powers up. Leave bit 1 = 0.
Caution
The Stepper phasing technique is a search operation which requires the
motor to move, typically in small steps. Nevertheless, caution should be
taken.
Example:
Note
The computed
Motor[].PhaseFindingTime
must be greater than 255
and less than 32,768 for the proper implementation of the automatic
stepper phasing technique.
Issuing a
#n$
or setting
Motor[].PhaseFindingStep = 1
launches the stepper phasing search move. The
pass/fail of the operation is reported by the motor status
Motor[].PhaseFound
bit. If the phasing fails
(
Motor[].PhaseFound = 0
) repeatedly:
Try increasing the magnitude,
Motor[].PhaseFindingDac
.
Try extending the time allowed for phasing,
Motor[].PhaseFindingTime
.
Try reversing the encoder decode
PowerBrick[].Chan[].EncCtrl
(e.g. 7 to 3 or vice versa).
Not applicable to serial encoders.
Try swapping two of the motor leads.
Decouple the motor from the load, and try again.
GLOBAL
Mtr1PhasingTime =
1000
;
// Total phasing time [msec] --User Input
Motor[
1
].PhaseFindingTime = Mtr1PhasingTime *
0.5
/ (Sys.ServoPeriod * (Sys.RtInt
1
))
Motor[
1
].PhaseFindingDac = Motor[
1
].I2TSet /
2
// Phasing search magnitude --User Input
Motor[
1
].AbsPhasePosOffset =
2048
/
5
// Qualifying motor movement
Содержание PBC Series
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Страница 204: ...Power Brick Controller User Manual Appendix B Digital Outputs Schematic 204 APPENDIX B DIGITAL OUTPUTS SCHEMATIC...
Страница 205: ...Power Brick Controller User Manual Appendix C Analog I Os Schematics 205 APPENDIX C ANALOG I OS SCHEMATICS...
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