VT-SR2-1X/1/SO43A-1608

The VT-SR2-1X/1/SO43A-1608 is an electronic signal and relay module produced by Bosch Rexroth Indramat for the VT-SWMA Modules series. Installed in a 19-inch rack, the board supplies regulated power rails and switching outputs so that hydraulic or general automation controllers can distribute stable reference voltages and energize auxiliary relays without separate power supplies. By combining low-current regulation with onboard relay drivers, the card simplifies control cabinet wiring and protects upstream command sources from high coil inrush.

A command source sees an input impedance of 50 kΩ, which minimizes loading on analog controllers while helping reject noise. Field wiring terminates on a 32-pin DIN 41612 Form D connector, allowing the module to be removed without disconnecting individual conductors. The module accepts a dual supply of ±24 VDC; these voltage rails power the internal reference circuits and relay driver stage. The module has a maximum current draw of 150 mA, so several cards can share a common cabinet supply without exceeding a typical 2 A auxiliary rail. An internal regulator generates a stable output of ±15 VDC for external sensors, command potentiometers, or low-power analog electronics connected to the same backplane.

The relay coil has a resistance of 700 Ω, allowing direct operation from the board’s transistorized output while keeping heat dissipation low. Its nominal coil voltage of 26 V supports relay operation, while the contact set transfers logic-level signals or pilot currents. A maximum switching delay of 4 ms keeps hydraulic valves or interlocks responsive to fast program scans. When the control voltage approaches the supply ceiling, the module tolerates an upper voltage limit of ±28 VDC without overstressing its components. Relay pickup begins at 24 V, and the relay releases near 13 V. An auxiliary protection threshold of ±22 V helps prevent relay chatter during brownouts while regulated power remains available for connected external loads.