Trio Motion Coordinator Euro 205, Technical Reference Manual

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4-28 Daughter Boards
SSI Servo Encoder Daughter Board
Trio Motion Technology
Software: The number of bits to be shifted in from the encoder attached to the SSI port
is set using the
SSI_BITS
axis parameter. This parameter defaults to 0 on
power up and this disables the reading of the encoder position into the MPOS
parameter. As soon as
SSI_BITS
is set to a value in the range 1 - 24 the MPOS
parameter will be set with the current position of the encoder and will then
follow the position of the encoder until the controller is powered down or
SSI_BITS
is set to 0. For example if a 12 bit multi-turn encoder with 12 bits
per turn is being used the command:
SSI_BITS=24
should be put at the start of the program or typed on the command line.
The SSI daughter board returns axis parameter ATYPE of 7. The servo function
can be switched on or off with the
SERVO
axis parameter:
>>SERVO=ON
When the servo function is OFF the value in the axis parameter DAC is written
to the 12 bit digital to analog converter.
Therefore:
Note: The daughter board hardware inverts the voltage relative to the DAC
parameter.
>>DAC=2047
This will set -10volts on voltage output when servo is OFF
>>DAC=0
This will set 0volts on voltage output when servo is OFF
>>DAC=-2048
This will set +10volts on voltage output when servo is OFF