Product Details

Baumuller 3.7817C, also marked as 37817C, is a legacy rack plug‑in relay output board and contact signal PCB designed for Baumuller rack automation and servo control systems. This relay output board provides isolated dry contact relay outputs for critical machine status, fault indication, brake release, pump control and safety alarm signals. The contact signal PCB integrates reliable signal driving circuits, power relay assemblies and status indication LEDs, converting low‑voltage logic signals from the rack controller into high‑potential switch contacts to drive external actuators, warning lamps and auxiliary contactors. Each relay channel features surge suppression to protect contacts from inductive load kickback. The multi‑layer FR4 circuit board is conformal coated to guard traces, drive chips and relay components against dust, moisture and corrosive vapors inside industrial control cabinets. As an obsolete and hard‑to‑source discontinued spare, it serves as a direct drop‑in replacement to restore isolated relay switching and auxiliary actuator control for ageing Baumuller control racks.

Basic Parameters

Brand: Baumuller

Model: 3.7817C, alternative marking: 37817C

Product Type: Isolated relay output PCB card

Main Function: Logic‑driven relay switching, dry‑contact status output, fault alarm routing, auxiliary actuator control, inductive load surge suppression

Interfaces: Relay contact terminal block, rack backplane edge connector, per‑channel status and fault LED indicators

PCB Treatment: Conformal coated multi‑layer circuit board, UL 94V‑0 flame retardant

Mounting: Plug‑in installation for compatible legacy Baumuller control racks

Auxiliary Supply: 24 V DC logic supply

Net Weight: Approximately 240 g

Condition: Original discontinued industrial spare

Supported Functions

This relay output board supports high‑reliability switching of auxiliary plant equipment based on control logic. The contact signal PCB receives digital command signals from the rack master controller and energizes the corresponding relays to close or open external circuits for brake control, fault beacons, cooling fans and interlock contactors. It continuously monitors driving channel integrity and reports drive circuit faults back to the main controller. It works cooperatively with digital I/O boards, encoder feedback boards and fieldbus communication modules to complete the machine safety and auxiliary actuation sequence. If this relay control card fails, the machine loses hard contact alarm and brake control signals and cannot trigger external auxiliary devices automatically.

Core Functions

The core function of this relay output board is to provide galvanically isolated dry‑contact switching between the low‑voltage control rack and external high‑voltage auxiliary loads. It separates sensitive control logic from noisy inductive loads to avoid back‑EMI damage to the rack system. Each relay channel can be configured for normally open or normally closed logic to match the original machine safety design. This contact signal PCB is an indispensable spare to rebuild the auxiliary actuation and alarm output layer of legacy motion machinery and retain the original hardwired safety logic.

Hardware Specifications & Environmental Features

Operating Temperature: 0°C ~ +60°C

Storage Temperature: -20°C ~ +75°C

Relative Humidity: 5%–95%, non‑condensing

Housing: Bare coated PCB with screw terminals for relay contacts

Protection: Relay surge absorption, ESD protection for logic ports, overcurrent protection for drive circuits, IP20

Anti‑interference: Separation of logic and contact power paths, RC snubber circuits to suppress electromagnetic noise inside cabinets

Compatibility: Suitable for legacy Baumuller modular control racks and matched servo drive units

Industry Applications: Applied in legacy petrochemical distributed control, old paper making production automation, material handling conveyor lines, packaging and textile machinery, water treatment remote signal collection and large conveyor remote I/O control racks.

Note: Confirm 800 series backplane compatibility, pulse signal type, counting mode and preset logic before ordering.

This is from our current stock.

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