The VT-VSPA proportional amplifier series consists of analog valve amplifier cards in Eurocard format designed for control-cabinet installation to drive proportional directional and proportional pressure valves.
They accept multiple command sources—including a differential ±10 V input, a 4–20 mA current input, and selectable preset command value inputs—which are summed internally with a zero-point offset to form the control signal. An enable function gates the output stage and feeds the command signal through a ramp generator so valve movement can be softened instead of stepping abruptly, with ramp behavior configurable (including ramp on/off and optional selectable ramp times). Output shaping includes adjustable characteristic correction (separate step/maximum settings for positive and negative directions) plus amplitude limiting to keep the command signal within the nominal operating range. The cards use an internal DC/DC power supply with inrush/making-current limiting and reverse-polarity protection, and they provide a clocked, current-limited, short-circuit-protected solenoid drive along with status/measurement points for setup and troubleshooting.
