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 | |||
| [email protected] | |||
| Mobile | +8615980777398 | ||
| +8615980777398 | |||
| 15980777398 |

Brand: ABB
Series: S800 / AC 800M / 800xA Automation Accessories
Product Type: CEX‑Bus Terminator Module
The TB851 (3BSC950194R1) is a passive terminator module designed for CEX‑Bus communication networks in industrial automation systems. It ensures signal integrity by eliminating reflections at the end of a bus line, which is critical for reliable communication between controllers and I/O modules in AC 800M and 800xA distributed control systems.
This module is compact, lightweight, and DIN-rail mountable, requiring no external power or maintenance. Its design guarantees long-term reliability in harsh industrial environments.
| Parameter | Specification |
|---|---|
| Model | TB851 |
| Part Number | 3BSC950194R1 |
| Function | CEX‑Bus Terminator |
| Bus Compatibility | CEX‑Bus |
| Voltage Requirement | Passive, no power required |
| Bus Connector | 25‑pin DB25 female |
| Mounting Type | DIN rail / Panel mount (S800 compatible) |
| Dimensions (H×W×D) | 55 × 16 × 45 mm |
| Weight (kg) | 0.04 |
| Operating Temperature | 0–55 °C |
| Storage Temperature | −40–+70 °C |
| Humidity | 5–95 % non‑condensing |
| Environmental Compliance | RoHS, CE, UL |
| Compatibility | AC 800M, 800xA systems |
Termination of CEX‑Bus lines in control cabinets
Process automation networks
Oil & gas, chemical, and petrochemical plants
Power generation and substation monitoring
Water and wastewater treatment systems
Mining and material processing automation
Manufacturing production lines requiring reliable bus communication
Signal Integrity: Eliminates reflections, preventing data errors.
Compact & Lightweight: Small footprint; easy panel installation.
Maintenance-Free: Passive design, no power required.
Easy Integration: DIN rail or panel mount installation.
Industrial Compatibility: Works with AC 800M and 800xA systems.
| Model | Description | Basic Parameters |
|---|---|---|
| TB840A | S800 CEX‑Bus terminator | Dimensions 55×16×45 mm, Weight 0.04 kg |
| TU842 | AC 800M termination unit | DIN rail mount, passive, similar bus interface |
| TU810V1 | Compact S800 module terminator | Small size, CEX‑Bus compatible |
| TU845 | S800 I/O termination unit | Standard S800 DIN mounting |
| CI872K01 | AC 800M communication interface | Interface module for bus networks |
| Model | Category | Key Features |
|---|---|---|
| PM861AK01 | AC 800M CPU module | Central controller CPU |
| PM867 | High-end processor | Redundant CPU, advanced performance |
| AI810 | Analog Input Module | 8-channel AI, S800 system |
| DP840 | Pulse Counter Module | Counts pulses, specialty I/O |
| CI840A | Profibus DP Interface | Communication interface for Profibus |
Q1: What is the TB851 used for?
A1: It terminates the CEX‑Bus line to prevent signal reflections and maintain communication integrity.
Q2: Does it require external power?
A2: No, it is a passive module and operates without power.
Q3: Where should it be installed?
A3: At the end of the CEX‑Bus line in the control system cabinet.
Q4: Which systems is it compatible with?
A4: ABB AC 800M and 800xA distributed control systems.
Q5: Can it be reused in another installation?
A5: Yes, if the module is still functional and properly installed.
Q6: What happens if the terminator is missing?
A6: Signals may reflect back, causing data errors or communication failures.
Q7: What environmental conditions can it handle?
A7: Operating temperature 0–55 °C, storage −40–+70 °C, humidity 5–95 % non‑condensing.
Q8: How is it mounted?
A8: On a DIN rail or panel mount with standard screws.
Q9: Does it provide diagnostic feedback?
A9: No, it is passive; status is monitored indirectly through bus performance.
Q10: Is it compliant with environmental standards?
A10: Yes, it is RoHS and CE compliant.