Model Number Explanation

05704: System 57 / 5704 series (fire & gas detection)

A: Standard assembly

0145: 4‑channel control card, 4–20 mA input

Technical Specifications

Input Type: 4–20 mA analog transmitters (2‑wire loop‑powered)

Channels: 4 independent, isolated channels

Measurement Range: 0–25 mA (linear, overrange capable)

Loop Power: Isolated 24 VDC ±5%, 25 mA max per channel

Max Line Resistance: 500 Ω (including sensor/transmitter)

Isolation: >±50 VDC breakdown to system ground

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

Power Consumption: 7.5 W typical; 8.3 W maximum

Display: Backlit 4‑part LCD (bar graph + digital + alphanumeric)

Indicators: Per‑channel LEDs (A1/A2/A3/Fault/Inhibit); Power/Attn LEDs

Form Factor: 3U × 1” (25 mm) wide, 19” subrack mount

Dimensions: 132 × 25 × 172 mm (H×W×D)

Weight: ~170 g

Operating Temp: −20°C to +60°C

Certifications: CE, TUV, UL 508, CSA

Key Features

4–20 mA support: Optimized for 2‑wire loop‑powered gas transmitters

4‑channel monitoring: Independent alarm configuration (A1/A2/A3) per channel

Loop power & protection: Isolated 24 VDC supply; short/open‑circuit protection

Electronic calibration: Zero/span adjustment via software (no potentiometers)

Fault detection: Open/short circuit, over/under range, transmitter failure

Hot‑swap capable: Insert/remove without rack shutdown

Local display: Real‑time concentration, peak hold, status, and diagnostics

Remote functions: Inhibit, reset, and status reporting via backplane

Applications

System Role: Primary monitoring card for analog gas detectors

Industries: Oil & gas, petrochemical, power, pharmaceuticals, water treatment

Gases Monitored: Toxic (H₂S, CO, NO₂), flammable, and VOCs; also temperature/humidity

Use Cases:

Fixed gas detection in hazardous areas

Plant safety and environmental compliance

Leak monitoring and perimeter security

Integration with DCS/PLC via Modbus or relay outputs

Compatibility

System: Honeywell System 57 (5704 fire/gas racks; 5701 gas racks)

Backplane: Standard 19” subrack backplane (24 VDC + data)

Replacement: Direct drop‑in; obsolete (EOL)—available as refurbished/used

Sibling Card: 05704‑A‑0144 (catalytic bead input version)

Critical Notes

This card is for 4–20 mA transmitters only (not catalytic bead or infrared sensors).

It is not a relay card—use 05704‑A‑0121 for relay output expansion.