Why the AI895 Exits the Typical 8-Channel Analog Input Module
Most 8-channel analog input modules group-isolate their channels and stop there. The AI895 does group isolation and adds three things a 4-20 mA loop in a hazardous area actually needs: HART digital comms passthrough, intrinsic safety certification, and a transmitter power supply built into the module. That combination removes the external safety barrier and the separate HART multiplexer from the cabinet layout, which is where most of the cost and panel depth usually goes.
The AI895 is the right pick when you have eight 2-wire transmitters in a Zone2 area, want to read digital HART tags from the same loop, and want the module certified for the installation rather than relying on a barrier to make the loop safe.
| Feature | Specification |
|---|---|
| Manufacturer | ABB |
| Part Number | AI895 |
| Brand | ABB |
| SKU | AI895 |
| 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 |
| Current limiting | Built in current limited transmitter power |
| CMRR, 50Hz, 60Hz | >80 dB |
| NMRR, 50Hz, 60Hz | >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 |
| CE mark | Yes |
| Electrical safety | EN 61010-1, EN 61010-2-201 |
| Hazardous Location | ATEX/IECEx Zone 2 with interface to Zone 0, cFMus C1, Div 2/Zone 2 with interface to C1, C2, C3 Div 1/Zone 0 |
| Marine certification | ABS, BV, DNV, LR |
| Temperature, Operating | 0 to +55 °C (+32 to +131 °F) |
| Temperature, Storage | -40 to +70 °C (-40 to +158 °F) |
| Pollution degree | Degree 2, IEC 60664-1 |
| Corrosion protection | ISA-S71.04: G3 |
| Relative humidity | 5 to 95 %, non-condensing |
| Max ambient temperature | 55 °C (131 °F), for vertical mounting in compact MTU 40 °C (104 °F) |
| Protection class | IP20 according to IEC 60529 |
| Mechanical operating conditions | IEC/EN 61131-2 |
| EMC | EN 61000-6-4, 61000-6-2 |
| Overvoltage categories | IEC/EN 60664-1, EN 50178 |
| Equipment class | Class I according to IEC 61140 |
| RoHS compliance | EU RoHS, UAE RoHS, CN RoHS |
| WEEE compliance | DIRECTIVE/2012/19/EU |
| Use with MTU | TU890, TU891 or TU891Z |
| Keying code | AE |
| Width | 45 mm (1.77") |
| Depth | 102 mm (4.01"), 111 mm (4.37") including connector |
| Height | 119 mm (4.7") |
| Weight | 0.2 kg (0.44 lbs.) |
Resolution is 12 bit with under/over range at 1.5 / 22 mA — the over-range margin above 20 mA is what lets the module distinguish a transmitter fault from a genuine process excursion.
AI895 vs the Other S800 8-Channel Analog Input Modules
ABB's S800 analog input range shares mechanics and Modulebus communication but splits by isolation level, channel count and signal type. The AI895 sits at the intrinsically safe end of that range:
| Related Part Number | Configuration Difference |
|---|---|
| AI801 | 8 channels, 0-20 mA / 4-20 mA, no HART — cheaper when you only need current loops |
| AI810 | 8 channels, voltage or current input, no HART digital passthrough |
| AI815 | 8 channels, HART compatible — safe-area counterpart, no intrinsic safety approval |
| AI825 | 4 channels only, but individually galvanically isolated per channel |
| AI845 | 8 channels, HART compatible, S800 series — closest safe-area alternative to the AI895 |
All ABB parts · I/O Modules · AI845 safe-area counterpart
Hazardous Area Installation on TU890 / TU891 Termination Units
The AI895 mounts on a TU890 (for Ex applications) or TU891 / TU891Z (for non-Ex) Compact MTU termination unit. Field wiring terminates at the MTU, not at the module, which means the module can be swapped without disturbing field conductors. Observe the keying code when seating the module and confirm the MTU variant matches the area classification of the installation.
Power comes from two sources and both must be present: the +5 V Modulebus supplies typically 130 mA, and an external +24 V supply provides typically 270 mA (max under 370 mA). The module draws power dissipation of 4.75 W across both rails.
What the Front Panel LEDs Tell You
The four front-panel indicators are Fault, Run, Warning and Tx. The Tx LED is the fastest way to confirm HART communication is actually happening on a given loop — if the process value reads correctly but the Tx LED never lights, the transmitter is not responding to the digital pass-through and the loop wiring, not the module, is the suspect.
Accuracy is typically 0.05% with a maximum of 0.1%, temperature drift typically 100 ppm/°C, and CMRR above 80 dB at 50/60 Hz. Rated insulation voltage is 50 V with a 500 V a.c. dielectric test.
Wiring for 2-Wire and 4-Wire Transmitters
The primary design target is 2-wire 4-20 mA transmitters powered from the module's built-in transmitter power. With the correct connection arrangement the AI895 will also interface a 4-wire transmitter and retain HART capability, but confirm that wiring arrangement against the module documentation before commissioning, since HART behaviour differs between the two connection methods.
Supply & terms: Stock status: In Stock · Condition: New · Warranty: One Year · Origin: Switzerland. Listed by AutoDCS Tech Parts Team · Last updated .
ABB AI845 · ABB AI801 · ABB AI825
Availability & Condition at AutoDCSTech
| Part Number | AI895 |
|---|---|
| Availability | In Stock |
| Condition | New |
| Warranty | One Year |
| Origin | Switzerland |
