ABB AI895 Analog Input Module – Reliable 8-Channel HART Interface
In hazardous process environments, accurate and safe analog signal acquisition is non-negotiable. The ABB AI895 Analog Input Module addresses this need directly: it interfaces 2-wire transmitters and, with a specific connection, 4-wire transmitters while retaining full HART capability. This 8-channel module integrates intrinsic safety components on every channel, eliminating the need for external safety barriers and simplifying cabinet design.
Each channel powers and monitors a two-wire process transmitter, with HART communication supported. The input voltage drop is typically 3 V (PTC included), and the transmitter supply delivers at least 15 V at 20 mA loop current to power Ex-certified transmitters, with overload current limited to 23 mA. This ensures robust operation even in demanding field conditions.
Key Features & Benefits
-
8 channels for 4...20 mA, single-ended unipolar inputs
- Integrated HART communication for remote configuration and diagnostics
- One group of 8 channels isolated from ground
- Powers and monitors Ex-certified two-wire transmitters
- Non-energy-storing analog inputs for externally powered sources
- Compact S800 mechanics – 45 mm wide, 0.2 kg
Technical Specifications
| Parameter |
Value |
| Article Number |
3BSC690086R1 |
| Signal Specification |
4...20 mA |
| Number of Channels |
8 |
| Signal Type |
Unipolar single ended |
| HART |
Yes |
| Intrinsic Safety |
Yes |
| Resolution |
12 bit |
| Isolation |
Groupwise isolated from ground |
| Under/Over Range |
1.5 / 22 mA |
| Error |
Typ. 0.05%, Max. 0.1% |
| Temperature Drift |
Typ. 100 ppm/°C |
| Input Filter (Rise Time 0-90%) |
20 ms |
| CMRR (50/60 Hz) |
>80 dB |
| NMRR (50/60 Hz) |
>10 dB |
| Rated Insulation Voltage |
50 V |
| Dielectric Test Voltage |
500 V a.c. |
| Power Dissipation |
4.75 W |
| Current Consumption +5 V Modulebus |
Typ. 130 mA |
| Current Consumption +24 V External |
Typ. 270 mA, Max. <370 mA |
| Operating Temperature |
0 to +55 °C (+32 to +131 °F) |
| Storage Temperature |
-40 to +70 °C (-40 to +158 °F) |
| Protection Class |
IP20 according to IEC 60529 |
| Dimensions (W x D x H) |
45 mm x 102 mm (111 mm with connector) x 119 mm |
| Weight |
0.2 kg (0.44 lbs.) |
Real-World Applications
The ABB AI895 excels in process industries such as oil & gas, chemical, and pharmaceutical plants where hazardous area compliance is critical. Its intrinsic safety rating (ATEX/IECEx Zone 2 with interface to Zone 0) allows direct connection to field transmitters in explosive atmospheres without additional barriers, reducing installation cost and complexity.
With HART capability, plant engineers can remotely configure and diagnose transmitters, minimizing downtime. For example, in a refinery, the AI895 can monitor pressure and temperature loops from a safe area while the transmitters remain in Zone 1, ensuring both safety and operational efficiency.
Installation & Setup Guidance
Mount the AI895 on an S800 DIN rail using the standard mechanics. Connect the 8-channel field wiring to a TU890 or TU891 Compact MTU – TU890 for Ex applications and TU891 for non-Ex. The MTU provides two-wire connections without extra terminals, simplifying installation. Ensure proper keying (code AE) to prevent mismatched insertion. For 4-wire transmitter connection, follow the specific wiring diagram provided in the module manual.
Maintenance & Reliability
With no moving parts and robust design, the AI895 requires minimal maintenance. Periodically inspect the front LEDs (Fault, Run, Warning, Tx) to verify communication status. Keep the module free from dust and moisture, and operate within the specified ambient temperature range (0 to +55 °C). The built-in current limiting protects the transmitter supply, enhancing long-term reliability. Using the AI895 reduces lifecycle costs by minimizing external components and field wiring.
Compatibility & Integration
The ABB AI895 is part of the S800 I/O system, compatible with ABB controllers via the Modulebus. It works seamlessly with TU890, TU891, and TU891Z MTUs. The module supports HART communication and is designed for integration with ABB's automation platforms, making it a versatile choice for new installations or system expansions.
Selection Guide & Purchasing Advice
Before purchasing, verify your system's compatibility with the S800 I/O family and confirm the required MTU type (TU890 for Ex, TU891 for non-Ex). Check the article number 3BSC690086R1 to ensure you receive the exact model. When sourcing replacement modules, choose a trusted supplier to guarantee authenticity and reliability. PLC Source PRO offers genuine ABB AI895 modules with fast shipping and responsive support.