Product Introduction
When process uptime is non-negotiable, the ABB AI845 delivers reliable analog signal acquisition for your control system. This 8-channel analog input module supports both voltage and current inputs, making it a versatile choice for demanding industrial environments. Designed for single or redundant operation, the AI845 ensures continuous monitoring even in critical applications.
Technical Specifications
Below are the key parameters that define the AI845's performance. Each value is sourced directly from the product datasheet.
| Specification |
Value |
| Number of channels |
8 |
| Signal specification |
0..20 mA, 4..20 mA, 0..5 V, 1..5 V |
| Resolution |
12 bit |
| Input impedance |
10 MΩ (voltage input), 250 Ω (current input) |
| Isolation |
Groupwise isolated from ground |
| Error |
Max. 0.1% |
| Temperature drift |
Max. 50 ppm/°C |
| Update cycle time |
10 ms |
| Max input voltage (non-destructive) |
11 V d.c. |
| Power dissipation |
3.5 W |
| Current consumption +5 V Modulebus |
100 mA |
| Current consumption +24 V Modulebus |
50 mA |
| Dimensions (W x H x D) |
45 mm x 119 mm x 102 mm (1.77" x 4.7" x 4.01") |
| Weight |
0.23 kg (0.51 lbs.) |
Industry Applications
The AI845 excels in process industries where precise monitoring of analog signals is critical. Typical applications include:
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Oil & Gas: Monitor pressure and flow transmitters with 4-20 mA loops.
-
Chemical Processing: Supervise temperature and level sensors with HART communication.
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Water Treatment: Control pump speeds and valve positions using 0-5 V signals.
Thanks to its redundant operation capability, the AI845 is ideal for safety-critical processes where downtime is unacceptable.
Installation & Setup Guidance
Mount the AI845 module on an S800 I/O rack using a compatible MTU (e.g., TU810, TU844, TU845). Ensure the MTU is correctly keyed (keying code CC) to prevent misinsertion. Connect field wiring to the MTU terminals, respecting the input type (voltage or current). For current inputs, the built-in current limiting protects the transmitter supply. Verify the module is seated firmly and the bus connector is engaged.
Maintenance & Reliability
Routine maintenance is minimal due to the module's solid-state design. However, periodic inspection of the field wiring and MTU connections is recommended. Keep the module within the operating temperature range of 0 to +55 °C (+32 to +131 °F) and ensure proper ventilation. The advanced on-board diagnostics, including front LED indicators for fault, run, and warning, allow quick status checks. With a mean time between failures (MTBF) not specified, but with robust construction, the AI845 offers long service life, reducing total cost of ownership.
Compatibility & Integration
The AI845 integrates seamlessly with ABB's S800 I/O system. It works with MTUs TU810, TU812, TU814, TU818, TU830, TU833, TU835, TU838, TU844, TU845, and TU854. The module supports HART pass-through communication, enabling smart transmitter configuration. For redundant setups, pair two AI845 modules to achieve fault tolerance.
Selection Guide & Purchasing Advice
Before purchasing the AI845, verify your system's compatibility with the S800 I/O architecture. Confirm the required MTU type based on your wiring needs (e.g., TU844 for per-channel voltage/current selection). Ensure the module's article number is 3BSE023675R1. For reliable sourcing, choose PLC Source PRO as your supplier, offering genuine parts with fast shipping.