User Signals - Matrox Rapixo CXP Installation And Hardware Reference

Auxiliary signals 43
of the rotating shaft, or of the sensor along the scale. For a given direction, the
encoder outputs the code in a precise sequence (either 00 - 01 - 11 - 10 or 00 -
10 - 11 - 01, depending on how the encoder is attached. If the rotating shaft, or
sensor moving along the scale, changes direction, the encoder transmits the Gray
code in the reverse sequence (00 - 10 - 11 - 01 or 00 - 01- 11 - 10, respectively).
Upon decoding a Gray code, the rotary decoder increments or decrements its
32-bit internal counter, depending on the direction of movement. You can
configure which Gray code sequence represents forward movement and
increments the counter; the reverse Gray code sequence will then represent the
backward direction and decrement the counter. You can specify the direction of
movement occurring when the Gray code sequence is 00 - 01 - 11 - 10, using
MdigControl() with M_ROTARY_ENCODER_DIRECTION.
The rotary decoder supports encoder frequencies of up to 50 MHz. The encoders
can only be connected to our LVDS auxiliary input signals. The LVDS receivers
on Matrox Rapixo CXP can support, under most circumstances, RS-422
signaling; refer to the electrical specification of the LVDS auxiliary input signals
in Appendix B: Technical information for requirements.
❖ Note that an external source must be used to power the rotary or linear encoder.
You can configure the rotary decoder's settings, using the MIL-Lite function
MdigControl() with M_ROTARY_ENCODER..., or by modifying the DCF file
with Matrox Intellicam.

User signals

Auxiliary signals can also be used to transmit or receive application-specific user
output and/or input.
If you want to start or stop an external event based on some calculation or analysis,
you can manually set the state of any auxiliary output signal (or I/O signal set to
output) to high or low. To do so, you set the state (on/off ) of a bit in a user settable
register (static-user-output register). When the bit is on, its associated auxiliary
output signal will be high; when it is off, the auxiliary output signal will be low.
This bit is referred to as a user-bit. To route the state of a user-bit to an auxiliary
output signal, use MdigControl() with M_IO_SOURCE and M_USER_BITn;
to set the state of a user-bit, use MdigControl() with M_USER_BIT_STATE.