Specifications

• Manufacturer: Westinghouse (Emerson)

• Model: 3A99859G01 (QHS‑R 486 / 56ACE)

• Type: Digital Input/Output Module (DI/DO)

• Architecture: Q‑Line (QHS‑R, right‑side slot)

• Channels: 16 isolated DI channels + 16 isolated DO channels

• Input Voltage: 24 VDC (nominal), 18–30 VDC range

• Output Rating: 24 VDC, 0.5 A per channel (sink/source configurable)

• Isolation: 1000 Vrms channel‑to‑ground (all channels)

• Response Time: <1 ms (DI), <2 ms (DO)

• Operating Temperature: 0 °C to 60 °C

• Power Supply: 24 VDC ±10%, 8 W typical

• Form Factor: Standard Q‑Line card, rack‑mounted

• Status Indicators: LED for power, communication, and channel status/fault

• Compatibility: WDPF, Ovation DCS (legacy systems)

• Weight: Approx. 1.1 kg

Key Features

• High‑Density I/O: 16 DI + 16 DO channels in one slot, optimizing rack space.

• Right‑Slot Design: Engineered for right‑side Q‑Line rack slots, matching legacy WDPF/Ovation layouts.

• Channel Isolation: 1000 Vrms isolation minimizes electrical noise and ground loops in harsh environments.

• Configurable Outputs: Sink/source selectable per channel for flexible field device compatibility.

• Fast Response: Millisecond‑level timing for critical interlock and sequence control applications.

• Diagnostic LEDs: Real‑time visual feedback for power, comms, and individual channel health.

• Hot‑Swap Capable: Online replacement without system shutdown, reducing maintenance downtime.

• Legacy Durability: Built for long‑term reliability in power plants, refineries, and heavy manufacturing.

Applications

• Power generation (boiler/turbine interlocks, burner management, auxiliaries)

• Petrochemical process control (valve interlocks, pump status, safety systems)

• Water/wastewater treatment (pump/valve control, level switch monitoring)

• Heavy manufacturing (conveyor control, machine interlocks, safety circuits)

• Legacy WDPF/Ovation system upgrades and spare part replacements

Related Part Numbers

• 3A99858G01: QHS‑R 486 combined analog I/O (right‑slot)

• 3A99858G02: QHS‑L 486 combined analog I/O (left‑slot)

• 3A99857G01/G03: QHS‑R 486 analog output (right‑slot, 8‑channel)

• 3A99857G02/G04: QHS‑L 486 analog output (left‑slot, 8‑channel)

Notes

• This is a legacy module, primarily used as a replacement/spare part for existing WDPF/Ovation installations.

• For new projects, Emerson recommends modern Ovation digital I/O modules for enhanced diagnostics and performance.