FBM212 P0914XL Thermocouple/mV Differential Input Module

The Differential Thermocouple/mV Input Module (FBM212) contains 14 differentially isolated thermocouple input channels, and one differentially isolated RTD reference junction temperature compensation channel (for terminal temperature sensing). Each thermocouple/mV channel accepts standard thermocouples for various temperature ranges, and each provides thermocouple burnout detection (up-scale). Each channel has a differential input to allow voltage differences between channels without introducing detected errors.
The module performs the signal conversion required to interface the electrical input signals from the field sensors to the optionally redundant Fieldbus. It executes an analog input application program, which provides configurable options for Conversion Time and Rate of Change Limits.

• 14 channels for input of thermocouple signals
• 1 isolated RTD reference junction compensation channel (for terminal temperature sensing)
• Each channel has a differential input
• Rugged design suitable for enclosure in Class G3 (harsh) environments
• Execution of an analog input application program that provides conversion time and configurable options for Rate of Change Limits
• High accuracy achieved by sigma-delta data conversions for each channel
• Termination Assemblies (TAs) for locally or remotely connecting field wiring to the FBM212

For high accuracy, the module incorporates a multiplexed Sigma-Delta converter, which can provide new analog input readings every 500 ms, and a configurable integration period to remove any process noise and power line frequencies. Each update time period, the Foxboro DCS Fieldbus Module (FBM) converts each analog input to a digital value, averages these values over the time period and provides the averaged value to the controller.

FBM212