The ABB TU890 (article 3BSC690075R1) is a compact Module Termination Unit for the S800 I/O family. This passive MTU connects field wiring and power supply directly to I/O modules. Additionally, it contains a part of the ModuleBus for system communication. The TU890 features gray terminals for field signals and process voltage connections. Maximum rated voltage reaches 50 V, while maximum current hits 2 A per channel. However, the specific I/O module design primarily constrains these values for certified applications. The 3BSC690075R1 distributes the ModuleBus to the I/O module and to the next MTU in line. It also generates the correct address by shifting outgoing position signals.
This termination unit offers several practical advantages for industrial installations. First, it supports intrinsic safety applications when used with AI890, AI893, AI895, AO890, AO895, DI890, and DO890 modules. Therefore, you can deploy it in hazardous locations. Additionally, the ABB TU890 enables compact installations of I/O modules. Field signals and process power connections are clearly separated.
Furthermore, mechanical keying prevents insertion of the wrong module. This feature reduces assembly errors significantly. The latching device secures the 3BSC690075R1 firmly to a DIN rail. DIN rail mounting makes installation fast and tool-friendly. The passive design means no active components fail over time.
The TU890 uses a terminal block connection type. It supports 8 channels per unit. Operating voltage is 24 V DC. Mounting orientation is horizontal with a 55°C maximum temperature. Use it specifically with I/O modules AI890, AI893, AI895, AO890, AO895, DI890, and DO890. Process connections use 27 blue terminals. The configuration supports single I/O only, not redundant.
For detailed electrical data, maximum current per I/O channel is 2 A. Dielectric test voltage reaches 500 V a.c. The 3BSC690075R1 accepts solid wire sizes from 0.2 to 4 mm² for process connectors. Stranded wires from 0.2 to 2.5 mm² (24 to 12 AWG) also work. Recommended torque for terminals is 0.5 to 0.6 Nm. For the power supply connector, acceptable wire sizes range from 0.25 to 2.5 mm² (24 to 14 AWG). Same torque applies.
The ABB TU890 carries multiple certifications for global use. CE mark confirms European compliance. Electrical safety follows EN 61010-1 and EN 61010-2-201. For hazardous locations, it qualifies for ATEX/IECEx Zone 2 with interface to Zone 0. Additionally, cFMus Class 1, Div 2/Zone 2 with interface to Class 1, 2, 3 Div 1/Zone 0 is supported.
Marine certifications include ABS, BV, DNV-GL, and LR. Therefore, you can use the 3BSC690075R1 on ships and offshore platforms. Operating temperature ranges from 0 to +55°C (+32 to +131°F). Storage temperature spans -40 to +70°C (-40 to +158°F). Relative humidity is 5 to 95% non-condensing. Pollution degree is Degree 2 per IEC 60664-1. Corrosion protection meets ISA-S71.04 G3 standards.
Maximum ambient temperature is 55°C for horizontal mounting. For vertical mounting, derate to 40°C. Protection class is IP20 according to IEC 60529. Mechanical operating conditions follow IEC/EN 61131-2. EMC compliance includes EN 61000-6-4 and EN 61000-6-2. Overvoltage categories meet IEC/EN 60664-1 and EN 50178. Equipment class is Class I (earth protected) per IEC 61140.
RoHS compliance follows EN 50581:2012. WEEE compliance adheres to DIRECTIVE/2012/19/EU.
The TU890 has a width of 64 mm including the connector. Edge-to-edge installed width is 58.5 mm. Depth measures 58 mm, or 106 mm including terminals. Height reaches 194 mm including the latch. Total weight is just 0.17 kg (0.37 lbs). This compact size saves valuable cabinet space.
1. Can I use the TU890 with redundant I/O configurations?
No, the ABB TU890 supports single I/O only. For redundant applications, please select a different MTU model from the S800 series.
2. What happens if I insert the wrong I/O module into this TU890?
Mechanical keying prevents insertion of incompatible modules. The 3BSC690075R1 is keyed specifically for AI890, AO890, DI890, and DO890 families. Wrong modules simply will not fit.
3. Is the TU890 active or passive?
The TU890 is a passive termination unit. It contains no active electronics. Therefore, it has no components that can fail. This design increases system reliability.
4. Can I mount this MTU vertically?
Yes, but derating applies. Maximum ambient temperature drops to 40°C for vertical mounting. Horizontal mounting allows up to 55°C.
5. Which intrinsic safety modules work with the TU890?
The ABB TU890 works with AI890, AI893, AI895, AO890, AO895, DI890, and DO890. All these support intrinsic safety applications with interface to Zone 0 hazardous areas.
| Brand Name | ABB |
| Model No. | DO890 |
| Product Type | Module Termination Unit |
| hasMerchantReturnPolicy | Adjust according to reality |
| Shippingdetails | Adjust according to reality |
