EHH-AMP-702-C-20 by Vickers

The EHH-AMP-702-C-20 is an amplifier card produced by Vickers within the Vickers Accessories series. This unit accepts low-level command signals and conditions them for use in industrial control loops, allowing PLC or controller outputs to work with field devices that need controlled current drive. By providing regulated power and signal shaping, it supports automation tasks that depend on stable proportional actuation and repeatable response. The card mounts inside standard control cabinets and serves as an interface between cabinet-level control hardware and downstream actuators.

At the electrical interface, the card operates from a nominal supply of 24 V DC and draws up to 35 W when delivering its maximum drive capability. The output stage can source up to 1.6 A, which suits proportional coils that require steady current rather than simple voltage excitation. Logic inputs are presented to a buffer with an impedance of 2700 ohms, which helps minimize loading on upstream controllers while maintaining noise immunity. Internally, the power devices switch at a carrier frequency of 1200 Hz, and this pulse-width-modulated operation supports smooth current control in the load. The card is intended for low-voltage control systems that need regulated coil drive and predictable signal behavior.

The circuitry tolerates up to 40 V DC on the supply terminals, giving the module headroom for transient overshoot without damage. Ambient operation is permitted up to +70 °C, so enclosure conditions must remain below that limit during continuous use. For fine positioning, the board can apply dither at 120 Hz, which helps reduce static friction in hydraulic components and improves low-speed response. User-selectable ramp generators can limit command changes to as long as 5 s or as short as 50 ms, allowing smoother acceleration and deceleration without external programming.