Model Number Explanation

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

A: Standard card assembly

0302: Single-channel, catalytic sensor input configuration (vs. 0301 for 4–20 mA)

Technical Specifications

Input Signal: Catalytic bead sensor (flammable gases: LEL, methane, propane, etc.)

Power Supply: 18–32 VDC (nominal 24 VDC)

Power Consumption: 3.75 W (typical, includes catalytic sensor)

Display: 4-character digital + 25-segment analog bar graph

Accuracy: ±1% FSD (full-scale deflection)

Resolution: 1% FSD (alarm setpoints)

Response Time: < 2 seconds

Operating Temperature: -40°C to +70°C

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

Dimensions: 170 × 25 × 112 mm (L×W×H)

Weight: ~0.165 kg

Certifications: CE marked

Key Features

Catalytic sensor optimized: Dedicated circuitry for flammable gas LEL monitoring

Multi-alarm logic: 3 alarm levels (A1/A2/A3: Alert/Warning/Danger) with independent relays

Front-panel display & LEDs: Local readout, alarm status, and fault indication

Sensor fault detection: Open/short circuit and drift monitoring (electronic drift < ±2%/6 months)

Remote inhibit/reset: External control for alarm suppression and reset

EEPROM configuration: Settings stored locally; no battery required

Applications

Industries: Oil & gas, petrochemical, power generation, pharmaceuticals, wastewater

Use Cases:

Fixed flammable gas detection systems (LEL monitoring)

Safety monitoring in hazardous areas (Zone 0/1/2)

Integration with plant DCS/PLC via optional 4–20 mA retransmission

High-integrity safety loops (single-channel mode)

Compatibility & Replacement

System Compatibility: Honeywell System 57 (5701 series racks)

Sensor Compatibility: Honeywell catalytic bead sensors (e.g., 2108N, 2109N)

Replacement Type: Direct drop-in for 05701-A-0302

Legacy Status: Obsolete (EOL); available as refurbished/used stock