User guide
Operational Theory Xenus XTL User Guide
16 Copley Controls Corp.
amplifier treats anything within the dead band ranges as zero, and subtracts the dead band value
from all other values. For instance, with a dead band of 100 mV, the amplifier ignores signals
between –100 mV and +100 mV, and treats 101 mV as 1 mV, 200 mV as 100 mV, and so on.
Input
Output
0
-100
-200
100
200
0 200-200 -100 100
Dead Band
Offset
To remove the effects of voltage offsets between the controller and the amplifier in open loop
systems, CME 2 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 amplifier for bi-directional operation from a uni-polar 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 2 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 Analog Position command operates as a relative motion command. When the amplifier
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 amplifier should be
homed every time it is enabled. The Homing sequence may be initiated by CAN, ASCII serial, or
CVM Indexer program commands.