Product Description:

The EHH-AMP-702-A-1-21 is an electronic amplifier module manufactured by Vickers within the Vickers Accessories series. It conditions low-level command signals and drives proportional solenoids or other inductive loads used in hydraulic or motion-control loops, allowing automation systems to modulate fluid power actuators with repeatable current rather than relying on direct voltage drive. By keeping the solenoid current independent of load impedance changes, the unit stabilizes valve positioning and helps maintain consistent process variables in industrial machinery.

The amplifier is powered from a regulated 24 VDC supply and presents an input resistance of 2.4 kΩ, so most PLC or joystick sources can deliver the reference without excessive loading. Output is enabled when the command exceeds 13 VDC and it turns off when the reference falls below 6 VDC, providing a defined dead band that prevents chattering in marginal signal regions. During normal operation, the card supplies up to 2 A of continuous load current, which is pulse-width modulated at a maximum 5 Hz switching frequency to minimize coil heating. Ripple is limited to 10% peak-to-peak, keeping magnetic force variations within tight tolerance bands. Because reverse-polarity protection is absent, the supply leads must be wired with the correct orientation at all times.

For field installation, the housing carries an IP67 rating, so dust ingress is blocked and temporary immersion will not affect functionality. Short acceleration or valve override events can draw a 2.1 A peak without exceeding the current foldback limits. The circuitry is specified to start at ambient temperatures down to -20 °C and maintain accuracy up to +70 °C, matching many outdoor mobile hydraulic environments. Connection to harnesses is through the ISO 4400 (DIN 43650) mounting interface, which provides a gasketed plug and a standardized connection across multiple proportional valve types.