Product Description:

The VT-PVAR-2-11/1 proportional amplifier card is manufactured by Bosch Rexroth Indramat for the VT-SSPA Plug-in Proportional Amplifiers series. Installed in a 19-inch rack, the module translates low-level PLC references into controlled currents for directional or pressure-controlled hydraulic valves used in industrial automation. By closing the electrical loop between the controller and the servo-hydraulic actuator, it allows valve response to be tuned without external signal conditioners.

The electronics draw a nominal backplane supply of 24 V DC, which is internally converted to an analog service rail of ±15 V at 40 mA for operational amplifiers and reference circuitry. Command inputs sourced from motion controllers present a load of 100 Ω; this fixed impedance limits current demand and protects upstream cards. With a Eurocard outline of 100 × 160 mm, the board mates directly with standard guide rails, while the exposed front edge rises to 128.4 mm for access to trimmers and test points without removing the carrier. Total power dissipation stays below 50 W, permitting convection cooling in most cabinets. An auxiliary output of ±10 V at 10 mA is available for transducer excitation. The amplifier can supply up to 15 mA to the valve coil when PLC override signals are absent.

The valve stage tolerates a maximum command resistance of 1 kΩ, ensuring stable current regulation across common proportional coils. Digital enable lines follow PLC logic, recognizing a HIGH signal above 12 V and a LOW signal below 6 V through an input impedance greater than 5 kΩ. The associated output channel can source 15 mA with a PLC supply of 24 V ±20%. Connection to the backplane is provided by 48 contacts on a DIN 41612 Style F header, allowing the card to be removed without rewiring the rack. The card weighs only 0.3 kg, limiting stress on the card guides and making the module easier to handle during installation or maintenance.