Product Description:

The VT-VSPA1-1-11B is a plug-in proportional amplifier card from Bosch Rexroth Indramat within the VT-VSPA Proportional Amplifiers series. Mounted in a Eurocard rack, it conditions command and feedback signals to drive pressure-control solenoid valves in automated hydraulic systems. By converting low-level electrical reference signals into controlled solenoid current, the module allows PLCs and motion controllers to regulate flow or force without separate power stages.

The card operates from a nominal supply of 24 VDC, with a permissible range between 22 V and 35 V that matches the +40%/-5% tolerance of machine power buses. Single-ended command channels accept up to +10 V, while a differential pair handles 10 V peak-to-peak. Current-mode interfaces are supported because the front end tolerates 20 mA and presents a 100 Ω input burden. There is an additional 9 V command path, a fixed 100 mA bias current, and a -9 V reference output rated at 25 mA for offset functions. Internally, ±9 V regulation powers the analog stages, and dither is generated at 370 Hz to minimize valve hysteresis. Command activity is observable through a 1 mV/1 mA monitor jack, and all terminations are routed through a 32-pin DIN 41612 Form D connector.

Protection is provided by a slow-blow fuse rated at 2.5 A. Under full load, the amplifier draws up to 50 VA and can source a continuous output of 1.6 A. The calibrated trimmer can raise the permissible solenoid peak to 1600 mA when higher valve actuation is required. The ramp generator limits step responses to a 30 ms minimum or a 1 s maximum set by the panel knob, which helps prevent hydraulic spikes. A ready output able to sink 50 mA reports module health, while total current consumption is capped at 1.8 A. Despite these functions, the card weighs only 0.1 kg, which helps when space is limited in densely populated control cabinets.