User guide

CME 2 User Guide Command Inputs
Copley Controls 71
7.1.1: Analog Command Notes
The amplifier can be driven by an analog voltage signal through the analog command
input. The amplifier converts the signal to a current, velocity, or position command as
appropriate for current, velocity, or position mode operation, respectively.
The analog input signal is conditioned by the scaling, dead band, and offset settings.
Scaling
The magnitude of the command generated by an input signal is proportional to the input
signal voltage. Scaling controls the input-to-command ratio, allowing the use of an optimal
command range for any given input voltage signal range.
For example, in current mode, with default scaling, +10 Vdc of input generates a
command equal to the amplifier’s peak current output; +5 Vdc equals half of that.
Scaling could also be useful if, for example, the signal source generates a signal range
between 0 and +10 Vdc, but the command range only requires +7.5 Vdc of input. In this
case, scaling allows the amplifier to equate +7.5 Vdc with the amplifier’s peak current (in
current mode) or maximum velocity (in velocity mode), increasing the resolution of control.
Dead Band
To protect against unintended response to low-level line noise or interference, the
amplifier can be programmed with a “dead band” to condition the response to the input
signal voltage. The 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