Product Description:

The VT-SR2-13/0-60 is a plug-in proportional amplifier card from Bosch Rexroth Indramat and belongs to the VT-SSPA Plugin Proportional Amplifiers series. Installed in a 19-inch rack or custom backplane, the board translates voltage commands from a PLC or analog controller into a calibrated, bidirectional current for a proportional valve stage. By shaping this current, the card allows industrial automation systems to modulate hydraulic pressure or flow with repeatable accuracy.

The board is powered by a symmetrical supply of ±24 VDC; operation remains stable between ±22 VDC and ±28 VDC, so standard machine supplies can be used without additional regulation. Internally generated auxiliary rails at ±15 VDC support the signal chain. A dither signal fixed at 340 Hz ±5% reduces valve hysteresis, improving small-step response. The power stage can deliver up to ±60 mA of valve current, a range suited to most single-coil proportional spools specified by Rexroth. Incoming command signals encounter a high impedance of 50 kΩ, preventing excessive loading on upstream electronics, while the enable circuit presents 700 Ω to accommodate typical safety-relay outputs. The Eurocard has dimensions of 100 × 160 mm, permitting direct insertion into standardized card frames and simplifying installation.

Overall current draw from the cabinet supply remains below 150 mA, limiting heat dissipation and allowing multiple channels to be stacked closely. Field wiring terminates on a 32-pin male DIN 41612 form D connector, keeping signal, power, and valve leads segregated on a single header. An onboard relay engages at 26 V and changes state in less than 4 ms, providing a consistent enable path for safety functions. With a mass of only 0.2 kg, the card adds minimal load to card guides, and its low inertia helps it withstand vibration in mobile or machine-mounted cabinets.