Our advantage
Global Logistics
We have a 10-year logistics and express cooperation agreement, so our products can be shipped to any place in the world.
Brand new and original
Our products are imported in bulk from the place of origin. Because of the cooperative relationship, our products are all original and 100% new.
24-hour service
We provide 7*24 hours service to our customers. We will be there whenever you need us.
Price advantage
All our products are priced very favorably because we have our own warehouse and supply.
| Company Information | |||
| sales@plc-automations.com | |||
| Mobile | +8615980777398 | ||
| +8615980777398 | |||
| 15980777398 |

The UFC921A101 is a versatile multi‑function control and interface board. It serves as a key processor for excitation systems in generator control setups such as UNITOL 5000 and as the INT‑2 control board within variable frequency converter (VFD) units, including the ACS range. It also integrates into process control networks like the Advant Master platform, ensuring precise signal and logic control in demanding industrial automation environments.
Brand: ABB
Series: UFC900 / INT‑2 Interface Boards
Model: UFC921A101
Ordering Code: 3BHE024855R0101
Product Type: Control/Interface Board — supports both excitation regulation and inverter control applications.
Multi-function integration – combines excitation regulation, logic control, and signal interfacing into one high-density module.
Precision control – rapid response for generator voltage regulation or motor speed via integrated AVR logic.
Rich I/O support – up to 8 analog inputs, 4 analog outputs, 16 digital inputs, and 8 digital outputs (depending on configuration).
Broad communication – supports Masterbus 300, Modbus, Profibus DP, CANopen, and others depending on system design.
Hot‑swappable design – can be replaced during operation, minimizing downtime.
Ruggedized build – conformal coating and varnishing ensure resilience in humid or contaminated environments.
Wide operating range – functions reliably across –25 °C to +70 °C, with humidity tolerance up to 95 % (no condensation).
Generator excitation control in UNITOL 5000 systems — delivering precise voltage and reactive power adjustment.
VFD internal control (INT‑2 board) within ACS drives — managing power electronics and motor commands.
Interface connection inside Advant Master process control systems — linking I/O devices over industrial bus networks.
Signal collection and distribution across analog/digital sensors, motor controllers, and PLC systems in process automation.
| Parameter | Specification |
|---|---|
| Model | UFC921A101 (3BHE024855R0101) |
| Functional Roles | Excitation Board / INT‑2 VFD Control / Process I/O Interface |
| Analog I/O | Up to 8 analog inputs (0–10 V, 0–20 mA, 4–20 mA); 4 analog outputs |
| Digital I/O | Up to 16 digital inputs; 8 digital outputs (24 V DC signals) |
| Communication Interfaces | Masterbus 300, Modbus, Profibus DP, CANopen (config‑dependent) |
| Environmental Range | Operating: –25 °C to +70 °C; Storage: –40 °C to +85 °C; Humidity: ≤95 % non‑condensing |
| Special Features | Hot‑swappable, varnished PCB for harsh environments |
| Mounting Dimensions (L×W×H) | Approximately 257 mm × 125 mm × 30 mm |
| Weight | Approximately 0.165 kg or up to 0.7 kg depending on configuration |
| Model | Function Type | Notes |
|---|---|---|
| UFC921A102 | Alternate Excitation/Inverter Board | Similar functions with enhanced filtering |
| UFC900A101 | Basic Interface/Signal Board | Ideal for simpler I/O tasks |
| UFC922A101 | Dual‑channel Excitation Controller | Adds redundancy for critical systems |
| INT‑3 Board | Next‑gen VFD Core Control | Extended functionality and I/O capacity |
| Advant I/O Module | Distributed I/O for Masterbus | Expanded analog/digital interface |
| Model | Product Type | Application Highlights |
|---|---|---|
| ACS880 Drive Module | Medium‑voltage VFDs | Used in pump, fan, and conveyor control |
| RDCU‑12C | Central Drive Control Board | Core logic processor for high‑end drives |
| AI810 | Analog Input Expansion Module | Adds precision I/O for automation systems |
| DCS880‑S02 | High‑power DC Drive Controller | Heavy‑duty motor control in industrial plants |
| RDIO‑01 | Digital I/O Expansion Board | Enhances I/O suite for complex systems |
Q1: What is UFC921A101’s main purpose?
A1: It serves as a multifunctional control board — for excitation systems, VFD control logic, or process control interfaces, depending on the system.
Q2: What I/O capacities does it support?
A2: Depending on configuration, it offers up to 8 analog inputs, 4 analog outputs, 16 digital inputs, and 8 digital outputs.
Q3: Can it remain operational during replacement?
A3: Yes — the board supports hot‑swappable replacement, reducing downtime.
Q4: How durable is it in industrial environments?
A4: It includes protective varnish/coating and supports wide temperature and humidity ranges for exceptional resilience.
Q5: What communication systems does it integrate with?
A5: It supports Masterbus 300, Modbus, Profibus DP, CANopen, and similar industrial protocols.
Q6: What’s its operating temperature span?
A6: From –25 °C to +70 °C, with storage capability down to –40 °C and up to +85 °C.
Q7: What role does it play in generator excitation?
A7: It controls excitation current via SCRs, maintaining stable voltage and reactive power regulation.
Q8: How is it used in VFD systems?
A8: Acts as the INT‑2 board, managing internal VFD functionality including power control and motor commands.
Q9: Can it integrate into DCS process systems?
A9: Yes — as part of the Advant Master platform, it handles I/O interfacing over Masterbus networks.
Q10: What makes it preferred over similar control boards?
A10: Its multifunctional design, hot-swap capability, ruggedization, and wide protocol support make it a versatile and reliable choice.
Authenticity guarantee
All product specifications are original and authentic imported products. We have an annual sales volume of 300 million yuan, and we only produce original and authentic products. All customers who cooperate with us directly online can enjoy low discounts.
Free warehouse
We have a complete range of product models, 80% of conventional models are in stock, and we have established channels in Asia, Africa, North America, South America, and Europe, effectively shortening the order processing time and satisfying customers in a timely manner.
Technical Team
Fast delivery. Spot goods can be shipped on the same day, and the delivery time transaction is 20% faster than that of peers on average, with a delivery time accuracy rate of 99%.
Thoughtful after-sales service
24-hour after-sales service guarantee team, professional and standardized management service system.