Foxboro P0926TM I/A Series Termination Assembly

Configured for field transmitter interface execution in I/A Series DCS networks, the Foxboro P0926TM, also cataloged as the P0926TM Termination Assembly, provides direct physical/electrical execution. This hardware assembly routes electrical signals from field wiring directly to specified Field Bus Modules, ensuring physical point-to-point signal connection without processing latency. The unit features built-in electrical isolation barriers and hardwired termination points configured to maintain signal integrity before digitization by the paired subsystem modules.

Hardware Specifications

Process Control & DCS Instrument Characteristics

The P0926TM incorporates dedicated physical pathways optimized for 4-20 mA HART loop protocol preservation. The copper traces and termination architecture are engineered to prevent capacitive loading across adjacent paths, ensuring that high-frequency digital HART communication signals superimposed on the 4-20 mA analog signal undergo zero attenuation. Channel-to-channel isolation is maintained via structural board layout barriers that prevent ground loops from corrupting the low-level analog data. Furthermore, when interfacing with thermocouple modules, the assembly utilizes stable terminal blocks to minimize thermal gradients across the junction points, facilitating accurate cold junction compensation (CJC) execution at the paired Field Bus Module interface.

Frequently Asked Questions

Q: Can the P0926TM termination assembly be replaced while the associated FBM is active?

A: Yes. The hardware design allows for modular hot-swap wiring maintenance, provided that field loop currents are safely isolated or bypassed to prevent transient surges across the FBM interface during terminal disconnection.

Q: What is the maximum torque specification for the screw-clamp terminal blocks?

A: The onboard industrial screw terminals accept wire sizes from 12 to 22 AWG and must be torqued to a maximum specification of 0.5 Nm (4.4 in-lbs) to prevent structural damage to the printed circuit board traces.

Q: How is the open-circuit and short-circuit diagnostic status transmitted?

A: The P0926TM is a passive component. It provides the physical connectivity paths that allow the active FBM diagnostic circuitry to continuously measure impedance thresholds and report loop faults to the I/A Series DCS system software.

Field Installation Guidelines

• Mounting Orientation and Clearance: Mount the assembly horizontally or vertically on standard 35 mm DIN rails inside an IP24 minimum rated industrial enclosure. Maintain a minimum clearance of 50 mm above and below the terminal blocks to facilitate appropriate field wiring bend radiuses and natural convection cooling.
• Shield Grounding Protocol: Earth grounding shields from field transmitter cables must be terminated at the designated cabinet instrument ground bar. Do not ground both ends of the signal shield to prevent the formation of detrimental ground loops across the DCS network.
• Wiring Separation: Route low-voltage analog signal lines (4-20 mA, RTD, thermocouple) through separate wire ducts isolated from high-voltage AC or DC power distribution cables to minimize electromagnetic cross-talk interference.
• Conductor Preparation: Strip field conductors to a length of 7 mm before insertion into the screw clamps. Ensure no loose strands extend beyond the terminal housing block to eliminate potential short circuits between adjacent channels.