Product Description:

The 422 is a DC servo amplifier manufactured by Copley Controls for the DC Servo Amplifiers series. The module supplies controlled motor current from a DC bus and accepts differential command voltages, allowing motion controllers to regulate motor torque in industrial automation equipment such as positioning tables, pick-and-place heads, and conveyor axes. With closed-loop bandwidth suited to medium-power servo motors, it forms the interface between low-level control electronics and the electromechanical load.

At its rated operating point, the amplifier delivers a continuous output of 10 A, while transient demands can be met with a peak of 20 A for up to 1 s. Dynamic response is supported by a current-mode bandwidth of 3 kHz, complemented by a voltage feedback bandwidth of 200 Hz for outer-loop regulation. Internal power devices are modulated by a pulse-width modulation scheme that switches at 25 kHz, keeping audible noise low and reducing ripple. The stage introduces only 0.2 Ω of output resistance, so armature voltage drop is minimal. Control logic becomes active 50 ms after the enable input changes state; this delay prevents spurious starts during power-up. The enable and direction inputs recognize high levels above the 2.5 V logic threshold. An auxiliary supply provides ±5 VDC at ±5 mA for external sensors or analog references.

Protective circuitry disables the output when the bus voltage rises to 185 VDC or falls below 22 VDC, and thermal sensors latch an overtemperature event at 70 °C. Command inputs tolerate differential signals up to ±20 V and present an impedance of 100 kΩ to limit loading on upstream converters. A programmable voltage monitor outputs the motor voltage divided by 20 and has a bandwidth of 200 Hz, allowing external diagnostic equipment to track the output voltage without requiring high-voltage probes. The scaled signal also allows a connected controller to monitor the power stage while remaining electrically isolated from the full motor voltage.