VT-VSPA Proportional Amplifiers

VT-VSPA Proportional Amplifiers are analog Eurocard valve amplifier cards used in control cabinets to drive proportional directional valves and proportional pressure valves. The cards can process several command sources, including a differential ±10 V signal, a 4–20 mA current input, and selectable preset command values. These inputs are combined internally with a zero-point offset to create the final control signal. An enable function controls the output stage and routes the command through a ramp generator, allowing valve movement to transition smoothly instead of changing abruptly. Ramp operation can be switched on or off, with selectable ramp timing available on applicable configurations. Signal shaping is handled through adjustable characteristic correction, including separate step and maximum settings for positive and negative directions, along with amplitude limiting to keep the command within the intended operating range. The cards also include an internal DC/DC supply with inrush-current limiting and reverse-polarity protection. For valve output, the series provides a clocked solenoid drive with current limiting and short-circuit protection, plus status and measurement points to support setup, adjustment, and troubleshooting.