FOXBORO P0926AH-B

Technical Specifications

• Analog Input Channels: 8 fully galvanically isolated analog input ports
• Supported Input Signal Ranges: 4–20 mA, 0–20 mA DC current loop signals
• A/D Conversion Resolution: 16-bit sigma-delta analog-to-digital converter
• Measurement Full-Scale Accuracy: ±0.03% of signal span at nominal operating temperature
• Input Channel Impedance: 250 Ω nominal loop impedance for 2-wire HART transmitters
• Channel Isolation Rating: 600 VAC one-minute withstand channel-to-ground isolation
• Channel Scan Update Rate: 100 ms full eight-channel sequential data refresh
• HART Communication Support: Built-in HART 5/7 modem for bidirectional smart transmitter parameter access
• Power Consumption: 3 W typical operating power via DCS backplane baseplate
• Operating Temperature Range: -40°C to +85°C
• Conformal Coating Class: G3 harsh environment anti-corrosion PCB coating
• Mounting Baseplate Compatibility: P0926KE dedicated DIN rail mounting base terminal assembly
• Physical Dimensions: 180 mm height × 65 mm width × 40 mm depth
• Net Weight: 0.37 kg
• Protection Rating: IP20 when mounted on matched baseplate inside control enclosures

Function Features

1. Eight independent isolated analog input channels supporting all standard industrial 4–20 mA process transmitters
2. Integrated HART modem enables real-time reading of smart transmitter diagnostic data, calibration parameters, and device status without separate HART multiplexers
3. High precision 16-bit ADC delivers ultra-stable flow, pressure, temperature, and level measurement for custody transfer processes
4. Continuous channel self-diagnostic function detects loop open-circuit, short-circuit, and transmitter power failure faults
5. Software-configurable channel filtering to suppress high-frequency electrical noise from variable frequency drives and high-voltage switchgear
6. DIN rail modular mounting design allows quick module replacement without full cabinet power shutdown
7. Conformal coated circuit board tolerates high humidity, salt spray, and trace chemical vapor in refinery and coastal power plant sites

Application Scenarios

• Refinery distillation column continuous pressure and temperature closed-loop control
• Power plant boiler feedwater flow and steam pressure monitoring loops
• Municipal water/wastewater treatment plant chemical dosing control transmitters
• Natural gas compressor station pipeline pressure and flow measurement
• Pharmaceutical batch production reactor temperature and pH transmitter signal collection

Working Principle

Material Composition

• Main PCB: FR4 high-temperature printed circuit board with G3 industrial conformal coating
• Module Housing: Extruded black aluminum heat sink casing for passive thermal regulation
• Isolation Hardware: High voltage withstand miniature isolation transformers, optocoupler isolation barriers
• Terminal Baseplate: Reinforced glass-filled nylon DIN rail base with nickel-plated copper screw terminals
• Internal Components: Low-drift precision metal film resistors, industrial ADC ICs, HART modem ASIC chip

Structural Features

• Vertical finned aluminum heat sink front panel for uniform heat dissipation across all eight analog channels
• Front panel multi-status LED array indicating backplane communication, module power, global channel fault, and HART active communication state
• Separate wiring zones on the baseplate to segregate incoming transmitter input wiring and backplane bus wiring
• Spring-locking DIN rail clip for fast mechanical installation on standard 35 mm TH35 mounting rails
• Keyed baseplate connector to prevent incorrect insertion of incompatible Foxboro I/A series modules

Installation Requirements

1. Mount the P0926KE dedicated baseplate first on standard 35 mm DIN rail before attaching the P0926AH-B module
2. Install inside IP54 rated industrial control cabinets to prevent dust and moisture contamination of PCB circuits
3. All field transmitter wiring must use shielded twisted pair cables; cable shield grounded once at the cabinet bulkhead terminal strip
4. Maintain minimum 12 mm horizontal clearance between adjacent analog I/O modules to avoid thermal crosstalk
5. Torque baseplate terminal wiring screws to 0.7 N·m to eliminate variable contact resistance affecting measurement accuracy
6. Route analog signal cables at least 20 cm away from high-current motor drive power cables to minimize electromagnetic interference

Usage Precautions

1. The module does not supply loop power to two-wire transmitters; an external 24 VDC power supply must be wired to the baseplate for transmitter excitation
2. Avoid exposing the module housing to direct sunlight for extended periods to prevent thermal drift of precision measurement circuits
3. Execute quarterly HART channel diagnostic scans to identify gradual transmitter signal degradation before process measurement errors occur
4. Do not apply over 30 VDC external voltage to input channel terminals; overvoltage will damage isolation transformers and ADC front ends
5. Prevent chemical solvent spills on the module’s aluminum housing and PCB edge connectors during cabinet maintenance
6. When replacing modules, match the exact P0926AH-B part number; alternate Foxboro I/O modules lack HART communication compatibility