VT-SR1-1X/ES43A8-2424

The VT-SR1-1X/ES43A8-2424 is an analog control card from Bosch Rexroth Indramat that belongs to the VT-SWMA Modules series. It acts as an interface between a motion controller and a proportional solenoid valve, shaping command signals into a precise current that drives the valve spool. Installation in a Eurocard rack provides a compact control module with dither, scaling, and relay functions for closed-loop hydraulic actuation in industrial automation. These functions allow the card to process low-power command signals before transmitting a controlled output to the connected valve.

The card draws only 0.15 A from its backplane, and its input stage has an impedance of 50 kΩ, so connected PLC outputs are not heavily loaded. The internal circuits use a stabilized supply of ±15 V, maintaining repeatable gain as cabinet voltages vary. A built-in oscillator injects dither at a frequency of 340 Hz with a tolerance of ±5%. The connected coil has a resistance of 700 Ω and converts the alternating component into a small mechanical vibration that minimizes static friction inside the valve. The peak-to-peak dither amplitude is fixed at 3 mApp, which remains below the magnetic saturation point while keeping the spool in constant micromotion.

Field wiring connects to the board through a 32-pin DIN 41612-D connector, and the solenoid channel can deliver up to 60 mA of continuous current at full command. An onboard relay engages when the cabinet supply reaches +24 V. Its armature closes within 4 ms, transferring control to the power stage without a perceptible delay. The output scale converts a -10 V command into a +60 mA valve current, allowing direct voltage control from proportional amplifiers. The Eurocard format measures only 100 × 160 mm, and the assembly weighs 0.3 kg, preserving rack space and load capacity for additional motion modules.