GE Field Control IC670ALG630 Thermocouple Input Module

Product Overview

The GE IC670ALG630 (IC670ALG630) is a high-performance 8-channel analog input module designed for the GE Field Control decentralized I/O system. This specialized module accepts 8 independent thermocouple or millivolt inputs, providing precise temperature monitoring for critical industrial processes such as power generation, chemical refining, and metal processing. By converting analog thermal signals into a 16-bit digital format (15 bits plus sign), the IC670ALG630 ensures high-resolution data acquisition, which is essential for maintaining system stability and reducing energy-intensive thermal fluctuations. Its ability to interface directly with various thermocouple types without external converters makes it a cost-effective solution for large-scale distributed temperature sensing.

Technical Configuration

The module architecture is built around a solid-state, optically-coupled multiplexer and an internal microprocessor that handles scaling, linearization, and advanced diagnostics.

• Input Versatility: Supports a wide range of thermocouples including Types J, K, T, E, S, R, B, N, G, C, D, and Platinel II.
• Cold Junction Compensation (CJC): Offers four flexible methods—Local (via thermistor), Remote (via BIU), Fixed (configured value), or None.
• Data Processing: Features self-calibration at power-up and every minute thereafter to compensate for ambient temperature shifts.
• Intelligent Diagnostics: Automatically detects and reports open thermocouple circuits, over-range/under-range conditions, and high/low alarm levels for each channel.
• Configurable Sampling: Users can select data acquisition rates based on 50 Hz or 60 Hz line frequencies to optimize normal mode noise rejection

Technical Specifications

Technical FAQs

How is data reported in the PLC memory?

Each channel can be configured to report either linearized temperature (in tenths of degrees Celsius or Fahrenheit) or raw millivolt values (reported as 1/100 of a millivolt).

What happens if a sensor wire breaks during operation?

Unless suppressed in the configuration, the module performs an "Open Thermocouple" check every time a channel is read. If a break is detected, a diagnostic bit is set in the discrete input table, and further processing of that channel is halted to prevent false readings.

Can this module operate without a separate power supply?

Yes, this module does not require a separate field power supply; it draws its required operating current (up to 195 mA) directly from the Bus Interface Unit (BIU) backplane.

Engineering & Installation Guide

• Cold Junction Accuracy: To ensure maximum precision when using local compensation, use the Thermocouple Terminal Block (IC670CHS004). If using standard terminal blocks, a 10K Ohm BetaTHERM thermistor must be installed at the terminals to avoid erroneous temperature reporting.
• Thermal Management: Avoid installing the IC670ALG630 and its terminal blocks in the same cabinet as high heat-dissipation assemblies. Temperature transients near the terminal connections can introduce CJC errors; maintaining a stable ambient environment is key to the +/-0.25 deg C CJC accuracy.
• Noise Mitigation: The module provides 120dB of Common Mode Rejection. For best results, use shielded thermocouple extension wire and terminate the shield at the terminal block ground. Ensure the DIN rail is properly grounded to chassis ground to facilitate the assembly’s internal grounding path.