Copley Controls Xenus Plus Series User Manual page 29

Xenus Plus User Guide 16-01344 Rev 06
Offset
To remove the effects of voltage offsets between the controller and drive in open loop systems, CME
provides an Offset parameter and a Measure function. The Measure function takes 10 readings of
the analog input voltage over a period of approximately 200 ms, averages the readings, and then
displays the results. The Offset parameter allows the user to enter a corrective offset to be applied
to the input voltage.
The offset can also set up the drive for bi-directional operation from a unipolar input voltage. An
example of this would be a 0 to +10 Vdc velocity command that had to control 1000 rpm CCW to
1000 rpm CW. Scale would be set to 2000 rpm for a +10 Vdc input and Offset set to -5V. After this,
a 0 Vdc input command would be interpreted as -5 Vdc, which would produce 1000 rpm CCW
rotation. A +10 Vdc command would be interpreted as +5 Vdc and produce 1000 rpm CW rotation.
Monitoring the Analog Command Voltage
The analog input voltage can be monitored in the CME control panel and oscilloscope. The voltage
displayed in both cases is after both offset and deadband have been applied.
Analog Command in Position Mode
The Xenus Plus Analog Position command operates as a relative motion command. When the drive
is enabled the voltage on the analog input is read. Then any change in the command voltage will
move the axis a relative distance, equal to the change in voltage, from its position when enabled.
To use the analog position command as an absolute position command, the drive should be homed
every time it is enabled. The Homing sequence may be initiated by CAN, EtherCAT, ASCII serial,
or CVM Indexer program commands.
Copley Controls 29