Product Overview

The Honeywell 05701-A-0329 functions as a high-density relay and analog interface module within the System 57 gas detection and control platform. This card processes complex safety signals to drive alarm peripherals, ventilation fans, and emergency shutdown (ESD) systems. It integrates eight Double Pole Change Over (DPCO) relays, providing dedicated outputs for three alarm levels (A1, A2, A3), fault conditions, and inhibit status. Simultaneously, the card generates a proportional 4–20 mA analog signal, allowing the System 57 to communicate gas concentration data directly to external DCS or PLC networks. This dual-functionality makes the 05701-A-0329 the primary interface for facility-wide gas safety and proportional process control.

Technical Specifications

Engineering Advantages

• Redundant DPCO Switching Logic: The Triple DPCO configuration provides both Normally Open (NO) and Normally Closed (NC) contacts for every alarm level. This flexibility allows engineers to design fail-safe circuits where a loss of power or a cable break automatically triggers a safety action, such as opening a ventilation damper or cutting power to a fuel valve.

• Proportional Signal Retransmission: Unlike simple relay cards, the 05701-A-0329 includes a high-precision 4–20 mA output. This enables real-time concentration monitoring on a supervisory SCADA system while the local relays handle immediate, hardware-based emergency actions.

• Critical Loop Isolation: Integrated galvanic isolation shields the System 57 backplane from electrical noise or ground loops generated by field-side actuators and long-distance cable runs. This protection maintains signal integrity for the entire rack, preventing a single faulty relay circuit from affecting adjacent sensor cards.

• Multi-Level Alarm Management: Dedicated relays for A1, A2, and A3 levels facilitate tiered response strategies. For example, a system can trigger low-speed ventilation at A1, high-speed exhaust at A2, and a full plant shutdown at the A3 threshold.

FAQs

• How many relays does the 05701-A-0329 provide in total?

  The card features 8 relays: six for alarm levels (two each for A1, A2, and A3), one dedicated to system faults, and one for inhibit status to signify maintenance mode.

• Is the analog output compatible with third-party PLCs?

  Yes. The standard 4–20 mA current loop interface ensures full compatibility with industrial controllers from Siemens, Rockwell Automation, ABB, and Yokogawa.

• Can I replace this card while the system is powered?

  No. The 05701-A-0329 does not support hot-swapping. You must power down the System 57 rack before installation or removal to prevent damage to the backplane communication pins.

• What is the condition of this unit?

  We supply the 05701-A-0329 as 100% Brand New and Original Honeywell equipment. Each unit ships in its original factory-sealed packing with full technical documentation and a 12-month warranty.