FOXBORO FBM237 P0914XS Analog Input Module

Technical Specifications:

• Number of Channels: 16 single-ended or 8 differential analog inputs
• Input Signal Types: 4-20mA, 0-20mA, 0-10V DC, 1-5V DC
• Input Resolution: 16-bit A/D converter (65,536 counts)
• Sampling Rate: 10 samples per second per channel (aggregate)
• Input Impedance (Voltage): Greater than 1 MΩ
• Input Impedance (Current): 250Ω burden resistor (user-selectable: 50Ω, 100Ω, 250Ω, 500Ω)
• Accuracy: ±0.1% of full scale (typical)
• Linearity: ±0.05% of full scale
• Common Mode Rejection: 120dB minimum (differential mode)
• Channel-to-Channel Isolation: 500V RMS
• Channel-to-Backplane Isolation: 500V RMS

Functional Features:

• Software-configurable input range per channel via I/A Series configurator
• Per-channel diagnostics: Open circuit detection, short circuit detection, out-of-range alarm
• Cold Junction Compensation (CJC): Built-in for thermocouple inputs (types J, K, T, E, N, R, S, B)
• Burnout current detection for 4-20mA inputs (21mA and 23mA test)
• Per-channel filtering: User-selectable 50Hz or 60Hz notch filter
• Per-channel scaling (engineering units conversion)
• LED indicators: Power, Run, Fault per channel group (4 channels per group)

Performance Parameters:

• Operating Temperature: 0°C to 60°C (32°F to 140°F)
• Storage Temperature: -40°C to 85°C (-40°F to 185°F)
• Relative Humidity: 5% to 95% non-condensing
• MTBF: Greater than 200,000 hours
• Power Consumption: 2.5W from backplane
• Isolation Voltage (Channel-to-Channel): 500V RMS
• Isolation Voltage (Channel-to-Ground): 500V RMS

Material Composition:

• Chassis: Galvanized steel with epoxy powder coating
• PCB: FR-4 glass epoxy, conformal coated
• Terminals: Phoenix-style screw terminals, tin-plated copper alloy
• A/D Converter IC: Analog Devices AD7714 or equivalent (16-bit sigma-delta)
• Isolation: Analog isolation amplifiers (Analog Devices AD202 or equivalent)

Structural Features:

• Form Factor: Standard I/A Series module, single-width
• Mounting: DIN rail or chassis mounting via backplane connector
• Dimensions (W x H x D): 25.4mm x 160mm x 120mm (approximate)
• Weight: Approximately 0.40 kg (0.88 lb)

Working Principle:
The FBM237 uses a sigma-delta A/D conversion architecture. Each channel has a dedicated multiplexer that routes the selected input to a 16-bit sigma-delta A/D converter. The analog input signal is first conditioned by an instrumentation amplifier with programmable gain, then converted to a digital value. Optical isolation barriers separate each channel from the backplane and from each other, preventing ground loops and cross-talk. The digital data is transferred to the I/A Series controller via the backplane I/O bus.

Advantages & Highlights:

• 16-bit resolution provides superior measurement accuracy compared to 12-bit modules
• Per-channel diagnostics enable early fault detection and predictive maintenance
• Software configurability eliminates need for hardware jumpers or DIP switches
• High common-mode rejection ensures accuracy in electrically noisy environments

Applicable Industries:

• Oil and Gas (wellhead monitoring, pipeline SCADA)
• Chemical and Petrochemical Process Control
• Power Generation (boiler control, turbine monitoring)
• Pharmaceutical (batch process monitoring)
• Pulp and Paper
• Water and Wastewater Treatment

Installation Requirements:

• Use shielded twisted-pair cable for all analog signals
• Ground shield at controller end only (single-point grounding)
• Do not run analog cables parallel to power cables; maintain minimum 300mm separation
• Verify input range settings in configuration software before connecting transmitters
• Connect 4-20mA transmitters in series loop configuration (2-wire)

Usage Precautions:

• Do not apply voltage inputs to current input terminals (will damage module)
• Do not exceed 30V DC on any input channel
• Enable burnout detection to identify wire breaks promptly
• Calibrate per-channel scaling after installation for accurate engineering units
• Replace fuse (if applicable) with exact Foxboro-specified rating only