Description
Note: Many products are not yet listed. Please contact us for more product information. Our supply channels are constantly expanding, and we currently have 20 stable shared supply channels. Please confirm the model, product, price, and all other necessary information with customer service before placing an order. We offer new, refurbished, and used products, and prices are adjusted according to the year of the item you require.
3. Key Technical Specifications
Confirm each line against the OEM datasheet and the label on your existing module before ordering. The S800 I/O build, baseplate part number, and firmware revision must match your station.
| Parameter | Value |
|---|---|
| Model | AO845 |
| Order Code | 3BSE023676R1 |
| Brand | ABB |
| Product Family | S800 I/O |
| Module Type | Analog output module |
| Output Channels | 8 |
| Output Signal Range | 4–20mA — verify supported ranges and scaling on your build |
| Resolution | Verify with OEM datasheet — confirm on the module label |
| Accuracy | Verify at 25 °C against the OEM datasheet |
| Load Capability | Verify maximum loop resistance against the field supply voltage |
| Isolation | Verify channel-to-channel and channel-to-bus isolation |
| Field Power | External 24V DC field supply required for loop-powered devices — verify wiring |
| Baseplate / MTU | Mounts on the S800 I/O baseplate or module termination unit — verify the correct part number |
| Communication | S800 I/O bus to the controller — verify station and firmware compatibility |
| Diagnostics | Open-loop and channel fault reporting — verify firmware support |
| Status Indicators | Module and channel status LEDs — verify arrangement |
| Operating Temperature | 0 °C to +60 °C (typical — verify for your cabinet) |
| Storage Temperature | –40 °C to +85 °C (typical — verify) |
| Humidity | 5% – 95% RH, non-condensing |
| Weight | Verify with OEM datasheet |
| Certifications | CE, UL, cUL — verify on the specific unit’s label |
4. Product Introduction
The ABB AO845 (3BSE023676R1) is an eight-channel analog output module for the S800 I/O platform. It drives 4–20mA field devices — valve positioners, I/P transducers, variable speed drives, and analog signal panels — from an S800 I/O station. The module converts the controller’s output commands into loop current and reports channel-level diagnostics back to the station.
The engineering value is the channel density and the diagnostics. Eight outputs on one module reduce the number of cards in a crowded station, and the open-loop detection tells the operator which loop has failed instead of leaving a valve stuck at the last command. Verify the baseplate and field power wiring before installation; the output loop needs an external 24V DC field supply.
AO845
AO845
AO845
AO845
5. Application Scenarios & Field Experience
Part 1 – Narrative Paragraph
The failure that wastes the most time on an analog output card is a channel that drifts instead of dying. The valve still moves, but the position no longer matches the command, and the loop tuning that worked last month no longer holds. Operators see it as a process problem. In my experience, the card is rarely the first suspect, and by the time it is pulled, the crew has already retuned the loop twice. When you replace an AO845, record the channel scaling and the field device calibration first.
Part 2 – Numbered List (Application Scenarios)
- Water Treatment – Chemical Dosing Pumps – The module drives 4–20mA setpoints to dosing pumps. The channel diagnostics report an open loop before the pump loses its setpoint.
- Power Generation – Damper and Valve Actuators – Used on boiler dampers and feedwater valves. The eight channels cover a group of actuators on one station.
- Pulp & Paper – Stock Preparation Valves – Drives I/P transducers on control valves. The external field supply must be sized for the total loop resistance.
- Oil & Gas – Compressor Anti-Surge Valves – The module commands anti-surge valve positioners. The open-loop detection helps isolate a failed output before the compressor trips.
Part 3 – Short Field Story
A water plant had a dosing pump that would not hold setpoint. The crew had replaced the pump and recalibrated the loop. The pump still drifted. We asked them to measure the current at the field terminal. The AO845 channel was outputting 3.8mA at a 4mA command — within the loop tolerance but enough to bias the pump. The plant replaced the module, transferred the channel scaling, and the pump held setpoint. The card had drifted, not the loop.
6. Standard Operating Procedure (SOP) for Quality Control
- Visual & Origin Inspection – Verify the ABB marking, AO845 model string, 3BSE023676R1 order code, and date code. Inspect the baseplate connector and terminals for bent pins or corrosion. Reject damaged connectors.
- Baseplate Fit Verification – Seat each module on an test baseplate and confirm full engagement and retention.
- Power-Up Self-Test – Power the module in a live station and verify it initializes without a bus fault.
- Output Channel Verification – Command each channel to 4mA, 12mA, and 20mA into a calibrated precision resistor. Verify accuracy and linearity against the OEM specification.
- Field Power and Load Test – Verify the output drives the rated loop resistance with the specified external 24V DC field supply.
- Diagnostic Test – Open one output loop and verify the module reports the fault to the controller.
- Firmware Documentation – Record the firmware revision and configuration. Flag any mismatch before shipping.
- ESD-Safe Packaging – Anti-static film, conductive foam, protected connectors, double-wall carton.
7. Frequently Asked Questions (FAQ)
Q1: Will the AO845 drop into my existing I/O baseplate?
A: It fits the I/O baseplate family, but the baseplate or module termination unit part number matters. Some bases support different field power arrangements and diagnostics. Check the baseplate part number in your station and confirm it accepts the . If you send us the baseplate model, we can confirm the match.
Q2: What is the warranty on this module?
A: We offer a 12-month warranty from the ship date. It covers output channel failure, isolation breakdown, bus communication failure, and connector failure under normal operating conditions. It does not cover damage from connecting field supply voltage to the output terminals, reversed field wiring, or ESD damage from handling without a wrist strap.
Q3: Do you have this in stock?
A: I/O inventory moves and varies by build. Confirm availability before you plan an outage. If we are out of the 3BSE023676R1 variant, we will tell you what we actually have rather than quote a date we cannot hold.
Q4: What happens if the firmware revision does not match my station?
A: The module may fail to initialize, or it may initialize but not report diagnostics correctly. A firmware mismatch is a common reason a replacement module does not integrate cleanly. Send us the revision from your old module and we will match it if we can.
Q5: Any installation pitfalls I should watch for?
A: Four. First, record the channel scaling and field device calibration before you pull the old module. Second, verify the external 24V DC field supply and the total loop resistance before you connect the load. Third, confirm the baseplate part number and the station addressing before power-up. Fourth, after the swap, command each channel through its range and measure the current at the field device before you return the loop to service. A module that powers up is not necessarily driving the loop correctly.
