Product Description:

The EEA-PAM-523-A-33 power amplifier card is produced by Vickers within the EEA-PAM Power Amplifiers series. It converts low-level command signals into controlled current for proportional solenoid valves used in hydraulic motion and pressure loops. The board mounts in a standard Eurocard slot and interfaces with a 24 VDC system bus, forming the link between PLC analog outputs and the valve coil so that stroke and flow follow the electronic reference.

Control electronics are energized from dual rails of ±15 V drawn through back-plane jumpers; the logic section requires no more than 50 mA Max. so it can share the same low-power auxiliary source used by the PLC. The input stage accepts voltage references from −10 V to +10 V, matching the industry standard ±10 V command span, and it presents a high-impedance load of 47 kΩ to avoid loading the DAC. A parallel current channel is provided for systems that issue a ±20 mA signal, allowing the card to convert either signal type into a proportional coil drive. Deadband is factory-trimmed to 25 % stroke and the open-loop gain is preset to 10 % per volt.

On the power side the amplifier draws energy from the machine’s 24 V bus; when line voltage falls below the 18 VDC shutdown threshold the coil output is disabled to protect the valve. Command current enters the summing node through a 100 Ω shunt, yielding the 1 V/A scale that also feeds the MP2 monitor pin. With zero volts applied, the card sources 0.3 A to hold the spool centered; under demand it can raise coil current to 1.6 A. The drive waveform is a PWM pulse stream so average current remains stable while power loss is minimized. A nominal supply of 24 VDC supports reference output of 5 mA, and the ±10 V reference rail is maintained to 1 % for external circuitry.