Model Number Explanation

05701: System 57 / 5701 series (Sieger gas detection system)

A: Standard card assembly

0502: 32-channel digital I/O card (32DI / 32DO relay)

Technical Specifications

Configuration: 32 digital inputs (24 VDC) / 32 digital outputs (relay)

Input Type: Sink/source, 24 VDC logic, optically isolated

Output Type: SPCO (Form C) relays, 1 A @ 24 VDC (resistive)

Isolation: Inputs/outputs isolated from backplane & each other

LED Indicators: Per-channel status LEDs (input ON, output energized)

Power Supply: 18–32 VDC (nominal 24 VDC, backplane-fed)

Power Consumption: ~4 W (max, all relays energized)

Operating Temperature: −20°C to +70°C

Form Factor: 3U × 1” wide rack-mount card (19” subrack)

Dimensions: 112 × 25 × 102 mm (L×W×H)

Weight: ~0.25 kg

Certifications: CE, SIL 2 capable (system level)

Key Features

High I/O density: 32DI + 32DO in one slot, reducing rack space

Relay outputs: Direct drive for external alarms, valves, and interlocks

Optical isolation: Noise immunity and safety separation between field and system

Per-channel LEDs: Quick visual status for every input/output

Hot-swap compatible: Insert/remove without shutting down the rack

Fail-safe design: De-energized state on fault for safety circuits

Applications

System Role: Digital I/O expansion for System 57 gas detection/safety racks

Industries: Oil & gas, petrochemical, LNG terminals, power, pharmaceuticals

Use Cases:

Monitoring gas detector fault/alarm contacts

Driving local/remote alarm beacons, horns, and annunciators

Interfacing with PLC/DCS via dry contacts

Safety interlock control for small motors/solenoids

Compatibility & Replacement

System Compatibility: Honeywell System 57 (5701 series 19” subracks)

Replacement Type: Direct drop-in replacement

Legacy Status: Obsolete (EOL); available as refurbished/used stock

Quick Comparison (0502 vs control cards)

0502: Pure digital I/O (32DI/32DO relay); no display/processing

0351/0361: Single-channel control (input + display + relays); no high-density I/O