Description
Product Introduction & Engineering Value
The FBM216b P0927AJ provides eight individually isolated 4-20 mA input channels with full HART communication capability. Two modules are installed together with a dedicated Redundant Adapter so that one operates as Master and the other as Tracker. Field wiring terminates to a single Termination Assembly.
Each channel has its own galvanic isolation from the other channels, from ground, and from module logic, plus an independent loop power supply. The pair supports any mix of conventional analog transmitters and HART devices (versions 5, 6, or 7). Communication with the control processor occurs over the redundant 2 Mbps Module Fieldbus. This combination is the preferred upgrade path when both channel isolation and module-level redundancy are required.
Technical Specifications
Configuration: Two FBM216b modules + matching Redundant Adapter (Master/Tracker)
Channels: 8, individually (channel) isolated
Supported Signals: 4-20 mA analog or HART FSK superimposed on 4-20 mA
HART Versions Supported: 5, 6, or 7
Isolation: Channel-to-channel, channel-to-ground, channel-to-logic (designed for 600 V ac, 1 min)
Analog Accuracy (includes nonlinearity): ±0.075% of full scale (typical for redundant configuration)
Temperature Coefficient: 50 ppm/°C
Resolution: 15 bits
Update Rate: 100 ms
Sense Resistor: Approximately 61.5 Ω nominal
Compliance Voltage (internal power): 18.5 V dc minimum at 20.5 mA
Power Requirements: 24 V dc +5% / –10% (redundant), 7 W maximum per module
Operating Temperature: –20 to +70 °C (–4 to +158 °F)
Field Application & The “Trench” Experience
A West Coast refinery replaced six older group-isolated redundant pairs with FBM216b P0927AJ modules on a catalytic reforming unit. The existing field cables and most Termination Assemblies were retained. After the swap, each channel retained continuous 4-20 mA values while the system gained independent isolation and reliable HART secondary-variable access. During a subsequent power-supply event on one Master module, the Tracker assumed control with no process-value interruption and no loss of diagnostic data.
Typical niche applications:
- Channel-isolated redundant pressure and differential-pressure transmitters on a multi-bed hydrocracker where ground potential differences exist
- Critical level and interface transmitters on a high-purity chemical storage system that cannot tolerate shared isolation groups
- Flow measurement banks on a continuous polymerization line requiring both uninterrupted analog values and periodic HART status under full redundancy
FBM216b P0927AJ
FBM216b P0927AJ
Transparency SOP: QA & Testing
Each P0927AJ pair is installed on a test baseplate with the correct Redundant Adapter and dual 24 V supplies. Master/Tracker establishment and controlled failover are verified first. Every channel on both modules then receives a calibrated 4-20 mA sweep while HART commands 0 and 3 are exchanged. Isolation resistance is measured channel-to-channel and channel-to-logic. The complete pair undergoes an elevated-temperature soak while analog accuracy and continuous failover capability are monitored. Only pairs that pass the full sequence are released.
The Veteran’s Tech Trap Guide
⚠️ Use the correct Redundant Adapter. The FBM216b requires its own adapter (commonly P0924DT for the standard version). The older P0917XQ adapter used with the group-isolated FBM216 is not compatible and will prevent proper Master/Tracker operation.
PRO TIP: Both modules in the pair must be identical hardware revision and carry matching application software. Mixing a P0927AJ with an earlier revision can cause intermittent failover or loss of HART messaging even though the analog signals continue.
⚠️ Channel isolation does not eliminate the need for proper external power practices. When external loop power is used on multiple channels, a Cable Balun module is still required to prevent HART signal cross-talk.
Dynamic FAQ
Q: What is the primary advantage of FBM216b P0927AJ over the earlier FBM216? A: Full individual channel isolation and independent loop power supplies on every channel, while still providing module-level Master/Tracker redundancy.
Q: Does the P0927AJ pair support HART version 7 devices? A: Yes. It is compatible with HART instruments compliant to versions 5, 6, or 7.
Q: Can I mix pure 4-20 mA transmitters and HART devices on the same redundant pair? A: Yes. Any combination is supported on a per-channel basis.
Q: Is field calibration required after installation? A: No. The modules leave the factory calibrated. No field adjustment is possible or necessary.
Q: Are New Surplus FBM216b units original Schneider Electric / Foxboro product? A: Yes. Units are original OEM material that have completed full analog accuracy, HART communication, isolation, and Master/Tracker failover testing.
Q: What warranty applies? A: 12-month warranty against defects in materials and workmanship from the date of shipment for both New Surplus and fully tested refurbished pairs.
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