Description
- Model: P0926AH-B (FBM201)
- Brand: Foxboro (Schneider Electric)
- Series: I/A Series / EcoStruxure Foxboro DCS
- Core Function: Interfaces 8 analog input signals to the Fieldbus
- Product Type: Analog Input Fieldbus Module (FBM)
- Key Specs: 8 Isolated Channels | 0–20 mA or 4–20 mA | 16-bit Resolution
- Number of Channels: 8, galvanically isolated
- Input Signal Range: 0 to 20 mA or 4 to 20 mA DC
- A/D Conversion: 16-bit Sigma-Delta converter
- Accuracy: ±0.03% of span
- Input Impedance: 250 Ω (nominal)
- Isolation Voltage: 600 V AC for 1 minute (Channel-to-Ground)
- Update Rate: 100 ms (all channels)
- Power Consumption: 3 W (typical)
- Mounting: DIN rail via a Baseplate (e.g., P0926KE)
- Environmental: Class G3 (Harsh) conformal coating
FOXBORO P0926AH-B
Application Scenarios & Pain Points
Engineering Pain Points: One of the primary challenges with the P0926AH-B is Field Power Sourcing. The FBM201 is a passive input module; it does not provide loop power to the transmitters. If you are using 2-wire transmitters, you must use an external 24 V DC power supply or a specific Termination Assembly (TA) that includes power distribution. I’ve seen many commissioning delays where the integrator expected the card to power the loop, only to find “Bad Quality” signals because the transmitter was unpowered.
Typical Application Scenarios:
- Process Variable Monitoring Reading pressure, flow, and level transmitters across chemical plants and refineries where signal isolation is critical to prevent ground loops.
- Environmental Monitoring Interfacing with gas analyzers or pH meters that require stable, high-resolution analog-to-digital conversion.
- Boiler Control Monitoring steam drum levels and feed-water flow where high accuracy is required for tight PID control.
- Legacy System Expansion Adding I/O capacity to older I/A Series racks (100 Series) via the newer 200 Series FBMs using migration baseplates.
The “Floating Ground” Case Study
Background: A paper mill in Canada was experiencing erratic “jitter” on four of their eight channels on a newly installed P0926AH-B. The signals would drift whenever a nearby large motor was started.
Problem: We checked the Termination Assembly. The integrator had grounded the cable shields at both the field transmitter and the DCS cabinet. This created a ground loop. While the P0926AH-B has excellent isolation, the high-frequency noise from the motor was capacitively coupling into the signal wires.
Solution: we followed the standard Foxboro grounding practice: shields were lifted at the field end and grounded only at the DCS baseplate.
Result: The signals became rock-solid. Integrator’s Lesson: Isolation in the module is a safety and precision feature, but it cannot overcome poor shielding practices in the field.
FOXBORO P0926AH-B
Compatible Replacement Models
| Original Model | Related/Replacement | Compatibility | Note |
| P0926AH-B | P0914BQ | ✅ Direct Replace | Earlier version of the FBM201; functionally identical |
| P0926AH-B | P0926AE | ❌ Incompatible | FBM204 version; handles 0-10V inputs instead of mA |
| P0926AH-B | P0926HM | ✅ Direct Replace | RH (Redundant Ready) version; check your baseplate type |
Integrator’s Tip: Always check the letter suffix. The “-B” indicates a specific revision or packaging style. In most DCS configurations, the software (I/A Series Letterbug) identifies the card as an “FBM201.” If you are replacing an older card, ensure the Termination Assembly (TA) part number (e.g., P0916AA) is compatible with the 200 series pinout.
Troubleshooting Quick Reference
| Symptom | Possible Cause | Related Part | Action |
| “Bad” Signal Quality | No Loop Power | ❌ External | Verify 24V DC is available to the transmitter |
| Module “F” (Fault) LED | Internal Hardware Fail | ✅ P0926AH-B | Reseat the module; check baseplate pins |
| Steady 0 mA Reading | Blown Fuse on TA | ❌ Termination | Check the individual channel fuses on the TA block |
| Inaccurate Reading | Scaling Mismatch | ❌ Software | Ensure 4-20mA range matches the block configuration |
Field Note: …When swapping these out, remember that the FBM201 is hot-swappable. However, the system will lose the signals for a few seconds. If those signals are tied to an E-stop or a critical interlock, put those loops in “Manual” or “Bypass” before pulling the module.
FOXBORO P0926AH-B
Strategic Quality Assurance (Our SOP)
- Channel Isolation Test: We verify 500V DC isolation between all 8 channels to ensure no cross-talk.
- Current Injection Sweep: Using a Fluke 789, we test 4.00, 12.00, and 20.00 mA to verify the 16-bit accuracy.
- Communication Stress: The module is placed on a test baseplate and monitored for “Bus Errors” over a 4-hour period.
- Physical Inspection: Verified for clean connector gold-plating and G3 conformal coating integrity.
Other Parts in Stock:
- Foxboro P0916AA (Termination Assembly)
- Foxboro P0922CP (FCP270 CPU)
- newplcdcs
- ABB PM866K01
- Honeywell CC-PAIH01
- Bently Nevada 3500/22M
- Triconex 3721
- Emerson KJ3203X1-BA1
