Delta Tau Geo MACRO, User Manual And Reference Manual

Page: 158 / 205

Geo MACRO Drive User Manual
146 Geo Macro Drive MI-Variable Reference
Secondary encoder Channel Node-Specific Gate Array MI-variables
MS{node},MI910 Secondary Encoder Decode Control
Range: 0 - 15
Units: None
Default: 0
MI910 controls how the input signal for the secondary encoder mapped to the specified node is decoded
into counts. As such, this defines the sign and magnitude of a “count”. The following settings may be
used to decode an input signal.
0: x4 quadrature decode
1: x1 quadrature decode
In any of the quadrature decode modes, PMAC is expecting two input waveforms on CHAn and CHBn,
each with approximately 50% duty cycle, and approximately one-quarter of a cycle out of phase with
each other. “Times-one” (x1) decode provides one count per cycle; and x4 provides four counts per
cycle. The vast majority of users select x4 decode to get maximum resolution.
MS{node},MI911 Secondary Encoder counter Direction
Range: 0 - 1
Units: None
Default: 0
MI911 controls the direction sense for the secondary encoder mapped into the specified node. It ca take
the following settings:
0: Clock-Wise (CW)
1: Counter-Clock-Wise (CCW)
The “clockwise” (CW) and “counterclockwise” (CCW) options simply control which direction counts up.
If you get the wrong direction sense, simply change to the other option (e.g. from 1 to 0 or vice versa).
Note:
If you change the direction sense of an encoder with a properly working servo
without also changing the direction sense of the output, you can get destabilizing
positive feedback to your servo and a dangerous runaway condition.