Aerotech UNIDEX 600 Series, User Manual

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Parameters U600 User’s Guide
C-24
Aerotech, Inc.
Version 1.4
C.2.46. HOMESWITCHTOL
To ensure the accuracy of a resolver based homing sequence, there must be a minimum
distance between the Home Limit Switch and the resolver null position. Otherwise, the
controller might miss the first resolver null and use the second as the home position
(before the Home Offset). The required distance depends on two factors: feedback
resolution and home feedrate. This parameter specifies the minimum distance in machine
steps that must exist between the home limit and the resolver null. Failure to maintain this
distance causes a HOME_SWITCH_TOLERANCE fault to occur.
This parameter is valid only for axis using resolver based feedback.
Be sure to set the Home Switch Tolerance bit in the FAULTMASK axis parameter to
enable the detection of this fault, then set the bit in the appropriate mask parameter
(DISABLEMASK, HALTMASK, AUXMASK, ABORTMASK, INTMASK and
BRAKEMASK) for the action to occur on this fault.
C.2.47. HOMEVELMULT
This axis parameter is used to scale the velocity during the home cycle after the home
limit has been found, while the marker (or resolver null) search is in progress. This allows
a high speed search for the home limit and a slower speed search for the marker,
providing a quick and accurate home cycle. For example, a value of 1 represents 1% of
the commanded home velocity (HomeFeedRateIPM or HomeFeedRateRPM task
parameters) during the marker search portion of the home cycle. The default value of 100
represents 100% of the commanded home velocity during the marker search portion of
the home cycle.
C.2.48. IAVG
The IAVG axis parameter is the actual current of the axis averaged over a time
determined by the IAVGTIME parameter. Units are in D/A (DAC) counts, where
±
32,767 represents
±
10 volts out of the D/A, which translates into +/- peak current by the
amplifier. This parameter is a read-only parameter.
C.2.49. IAVGLIMIT
This axis parameter detects an over current condition based upon the setting of the
IAVGTIME parameter. The value specified in the IAVGTIME parameter determines
what time period to average the instantaneous current (ICMD). An RMS current limit
fault occurs if the RMS average exceeds the limit set by this parameter. As with the
IMAX parameter, the range of this parameter is 0 to 32,767, where 10 volts is
represented by the value 32,767. To set this parameter, determine the command voltage
that the amplifier requires to produce the desired maximum RMS motor current.
IAVGLIMIT = (MaxV /10)* 32767, where MaxV is the voltage into the amplifier
producing the peak of the desired maximum RMS current level.
For example, the torque applied to the motor (in torque mode), may be easily calculated
for brush or brushless motors, knowing a few parameter values and the K
T
(motor torque
constant). The UNIDEX 600\650 Controllers have a 16 bit Digital-to-Analog converter
used to convert a signed 16 bit number (+32,767 through -32,767) to an analog voltage in