Aerotech UNIDEX 600 Series, Руководство пользователя

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U600 User’s Guide Parameters
Version 1.4
Aerotech, Inc.
C-33
output from the DAC. The voltage per bit is equal to the maximum voltage divided by the
maximum counts; 20/65,536 = .0003
.060/(20/2
16
) = 197 counts for the UNIDEX 600
C.2.71. PHASEBOFFSET
This axis parameter is used with the PHASEAOFFSET axis parameter to null any offset
in the DAC’s (commands) output to the drive for phase B (and Phase A) of a brushless
motor. Brush motors utilize the DACOFFSET axis parameter.
The value is entered as a signed number representing the number of D/A counts (+/-)
required to bring the DAC output command to zero volts. This value is added to all motor
command values before being output to the DAC.
For example, if an axis has a 60 mV (.060 volt) offset, -392 would be entered for this
parameter. This is calculated by dividing the offset by the voltage value of each step of
the DAC. UNIDEX 600 has a 16-bit DAC (+/- 32767 counts), generating a +/- 10-volt
output from the DAC. The voltage per bit is equal to the maximum voltage divided by the
maximum counts; 20/65,536 = .0003
.060/(20/2
16
) = 197 counts for the UNIDEX 600
C.2.72. POS
This axis parameter specifies the observed (as viewed from the primary feedback device)
position of the axis in machine counts. This parameter is a signed 32-bit integer having a
range of
±
2 E31 - 1 (approxi/- 2.1 billion). Upon initialization, the system sets
the current observed position (POSCMD) equal to the POS parameter value. At the
completion of a homing cycle, this parameter is set to the value of the HOMEOFFSET
axis parameter.
Normally, you would read this parameter, however, you may also set this parameter to a
value, which will not result in any axis motion, because the position command will be set
to the same value.
Setting this parameter will clear the “homed” condition of the axis (if it was previously
homed).
The PositionUnits machine parameter provides the actual axis position in user units.
C.2.73. POSCMD
The position command axis parameter is the current value of the position command, in
units of machine counts. In other words, this is the position the axis is being commanded
to move to. The actual position POS may differ at any given time, based on the
mechanics of the system. The PositionCmdUnits machine parameter provides the
command position in user units.
C.2.74. POSERR
The position error is the instantaneous difference, in counts, between the commanded
position (POSCMD) and the actual position (POS). POSERR = (POSCMD-POS); this
axis parameter is continuously updated on each servo loop cycle.