Product Overview
The ABB TU890 Industrial Automation Module is a compact Module Termination Unit (MTU) engineered for the S800 I/O system. This passive unit connects field wiring and power supply to I/O modules while housing a segment of the ModuleBus. Its gray terminals handle field signals and process voltage connections, with a maximum rated voltage of 50 V and a maximum rated current of 2 A per channel—values constrained by the certified design of the connected I/O modules.
Designed for intrinsic safety applications, the TU890 works seamlessly with AI890, AI893, AI895, AO890, AO895, DI890, and DO890 modules. It distributes the ModuleBus to the I/O module and the next MTU, generating the correct address by shifting outgoing position signals. Mechanical keying prevents incorrect module insertion, and a latching device secures the unit to a DIN rail for reliable horizontal mounting.
Technical Specifications
Below are the critical parameters for the ABB TU890, sourced directly from the manufacturer's data:
| Specification |
Value |
| Article Number |
3BSC690075R1 |
| Type |
Compact |
| Connection |
Terminal block |
| Channels |
8 |
| Voltage |
24 V |
| Mounting |
Horizontal (55 °C max ambient) |
| Process Connections |
27 blue terminals |
| Maximum Current per I/O Channel |
2 A |
| Wire Sizes (Process Connector) |
Solid: 0.2–4 mm²; Stranded: 0.2–2.5 mm², 24–12 AWG |
| Wire Sizes (Power Supply Connector) |
0.25–2.5 mm², 24–14 AWG |
| Recommended Torque |
0.5–0.6 Nm |
| Dielectric Test Voltage |
500 V a.c. |
| Operating Temperature |
0 to +55 °C (+32 to +131 °F) |
| Storage Temperature |
-40 to +70 °C (-40 to +158 °F) |
| Humidity |
5–95% non-condensing |
| Protection Class |
IP20 (IEC 60529) |
| Dimensions (W×D×H) |
64 × 58 × 194 mm (including connectors) |
| Weight |
0.17 kg (0.37 lbs) |
Industry Applications
The TU890 excels in process industries requiring intrinsic safety and compact I/O layouts. In chemical plants, it interfaces with AI890 analog input modules to monitor pressure transmitters in hazardous Zone 2 areas. For oil and gas applications, the TU890 supports DO890 digital output modules controlling solenoid valves, with mechanical keying ensuring correct module placement during rapid maintenance. Its DIN rail mounting and horizontal orientation simplify panel integration in skid-mounted systems, reducing wiring errors and commissioning time.
Installation & Setup
Mount the TU890 horizontally on a standard DIN rail using the latching device. Ensure the ambient temperature stays below 55 °C; for vertical mounting, derate to 40 °C. Connect field wiring to the 27 blue terminals, observing torque limits of 0.5–0.6 Nm. Use solid wires from 0.2 to 4 mm² or stranded wires from 0.2 to 2.5 mm² (24–12 AWG) for process connections, and 0.25–2.5 mm² (24–14 AWG) for power supply. Always verify the ModuleBus connection to the adjacent MTU to maintain proper addressing.
Maintenance & Reliability
The passive design of the TU890 minimizes wear, but periodic inspection is recommended. Check terminal torque annually to prevent loosening from thermal cycling. Keep the IP20 enclosure free of dust and moisture. With corrosion protection per ISA-S71.04 G3, the unit withstands harsh industrial atmospheres. Operating within the 0 to +55 °C range ensures long-term reliability; avoid exceeding the maximum ambient temperature to prevent premature aging of components.
Compatibility & Integration
This ABB TU890 is purpose-built for the S800 I/O platform. It pairs with AI890, AI893, AI895, AO890, AO895, DI890, and DO890 modules for intrinsic safety applications. The ModuleBus integrates seamlessly with ABB controllers, and the single I/O configuration supports redundant systems when paired with appropriate modules. Its compact design allows high-density installations without sacrificing performance.
Buying Guide
Before purchasing the TU890, confirm your I/O module compatibility and required channel count. Verify the article number 3BSC690075R1 to ensure exact match. For questions about integration or availability, PLC Source PRO offers genuine ABB spares with fast global shipping. Choose the TU890 for a reliable, certified termination solution in your S800 system.