Description

ABB UFC921A101 Isolated Analog Output Module

Technical Specifications

• Product Model: UFC921A101
• Full Part Number: 3BHE024855R0101
• Brand: ABB
• Warranty: One Year
• Input Voltage: 24 VDC (18–30 VDC tolerance)
• Operating Temperature: -20°C to +60°C
• Storage Temperature: -40°C to +85°C
• Response Time: ≤ 1.5 ms analog conversion latency
• Protection Class: IP20 rack-mounted enclosure
• Accuracy Class: 0.1% full scale (16-bit resolution)
• Output Frequency: 50/60 Hz system clock compatible
• Rated Current Range: 0–20 mA loop load per channel
• Communication Interface: Internal rack backplane bus
• Supported Protocols: ABB AC800M proprietary bus protocol
• Overload Capacity: Electronic short-circuit protection per individual output channel
• Dimensions: 148 mm × 103 mm × 32 mm
• 

Product Overview

The UFC921A101 is a 2-channel galvanically isolated 16-bit analog output expansion module engineered exclusively for the ABB AC800M DCS distributed control system platform. It converts digital control logic signals from the main processor into standardized 4–20 mA analog field outputs to drive control valves, variable frequency drives, positioners and local indicating instruments across process loops. The module addresses persistent field control issues including cross-channel signal interference, low conversion precision causing actuator hunting, limited expandable AO slots on base controllers, and damage from field wiring short circuits or reverse polarity. Independent channel isolation blocks ground loop noise commonly generated in large plant wiring networks and improves closed-loop regulation stability for critical process parameters such as temperature, pressure and flow. DCS system integrators, petrochemical and power plant automation engineers, and process maintenance technicians benefit from its compact rack footprint and fault segmentation design that prevents single-channel failure from crashing the entire control card. It executes continuous background diagnostics for circuit integrity, stores channel calibration data in non-volatile memory, and supports hot swapping within the DCS rack to minimise production interruption during module replacement.