User guide

Command Inputs CME 2 User Guide
74 Copley Controls
7.2.1: PWM Input Notes
Two Formats
The amplifier can accept a pulse width modulated (PWM) signal to provide a current
command in current mode and a velocity command in velocity mode. The PWM input can
be programmed for two formats: 50% duty cycle (one-wire) and 100% duty cycle (two-
wire).
50% Duty Cycle Format (One-Wire)
The input takes a PWM waveform of fixed frequency and variable duty cycle. As shown
below, a 50% duty cycle produces zero output from the amplifier. Increasing the duty
cycle toward 100% commands a positive output, and decreasing the duty cycle toward
zero commands a negative output.
Decreasing Duty Cycle Increasing Duty Cycle
Max -
Max +
0
PWM Input
Amplifier Output
50 % Duty Cycle
The command can be inverted so that increased duty cycle commands negative output
and vice versa.