Reference Manual

16-Axis MACRO CPU Software Reference Manual
16-Axis MACRO Station MI-Variable Reference 45
MS{node},MI927 Encoder Loss Status Bit
Range: 0 – 1
Units: none
Default: 0
MI927 reports whether the Servo IC on the 16-Axis MACRO Station has detected loss of a differential
encoder signal for the machine interface channel mapped to the specified MACRO node number. It is a
single-bit variable that reports 0 if no loss has been detected, or a 1 if a loss has been detected. It will still
report a value of 1 after a loss has been detected, even if the signal has been recovered, until a zero value
has been written to MI927 to clear the bit.
For this bit to work properly, the A+, A-, B+, and B- encoder inputs must also be wired into the T, U, V,
and W flags for the channel. Also, the resistor pack for the encoder channel must be reversed from the
standard configuration so that pin 1 of the pack (marked with a dot) is at the opposite end from pin 1 of
the socket (marked with a bold outline and square solder pin).
The shutdown function on encoder loss will work as long as the resistor pack has been reversed from
factory default. However, proper reporting of the exactly where the loss occurred requires double wiring
of the encoder into the flags so MI927 can detect the loss.
This encoder-loss status bit for each channel is copied into bit 8 of the flag status word of the matching
MACRO node for reporting back to PMAC if MI16 for the 16-Axis MACRO Station is set to 1.
If the T, U, V, and W flags are used for other purposes, such as Hall commutation sensors, or analog-
encoder sub-count data, the status of MI927 should be ignored.
MS{node},MI928 Compare-State Write Enable
Range: 0 – 1
Units: none
Default: 0
When MI928 is set to 1, the value of MI929 if forced onto the position-compare output for the channel
associated with the specified node. MI928 is automatically reset to 0 immediately after this occurs.
MS{node},MI929 Compare-Output Initial State
Range: 0 – 1
Units: none
Default: 0
The value of MI929 is forced onto the position-compare output for the channel associated with the
specified node when MI928 is set to 1. After this, each time the channel’s encoder-counter position
matches the value of MI925 or MI926, the output state is toggled.
MS{node},MI930 Absolute Power-On Position (Read Only)
Range: 0 – $FFFFFFFFFFFF
Units: counts
Default:
This variable, when queried, reports the value of the absolute position for the specified MACRO node.
MI11x for the motor node determines what type of feedback device at what address will be read when this
variable is queried.
When the value of MI930 is queried, the encoder counter for the channel matched to the specified node is
not cleared (when the otherwise similar MI920 is queried, the counter is cleared.)