Accelnet Plus Micro Modules User Guide
16-01687 Rev 03
Copley Controls
Page 116 of 139
O
FFSET
To remove the effects of voltage offsets between the controller and the 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.
M
ONITORING THE
A
NALOG
C
OMMAND
V
OLTAGE
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.
A
NALOG
C
OMMAND IN
P
OSITION
M
ODE
The Accelnet 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 must be
homed every time it is enabled. The Homing sequence may be initiated by CAN, ASCII serial,
CVM or CPL Indexer program commands.