DI-8B47 Linearized Thermocouple Input Modules

Types J, K, and T

Product Features

• Interfaces to Thermocouple Types J, K and T
• Linearizes Thermocouple Signal
• High Level Voltage Outputs
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1
• Input Protected to 240VAC Continuous
• 120dB CMR
• 70dB NMR at 60Hz
• Low Drift with Ambient Temperature
• CJC range: -40°C to +85°C
• CSA, FM, and CE Certifications Pending
• Mix and Match Modules

Products in the Series

DI-8B modules are an optimal solution for monitoring real-world process signals and providing high level signals to a data acquisition system. Each DI-8B47 module isolates, filters, amplifies, and linearizes a single channel of temperature input from a thermocouple and provides an analog voltage output.

Linearization is accomplished using a four breakpoint piecewise linear approximation.

The DI-8B47 can interface to industry standard thermocouple type J, K, and T and has an output signal of 0V to +5V. Each module is cold-junction compensated to correct for parasitic thermocouples formed by the thermocouple wire and screw terminals on the mounting backpanel. Upscale open thermocouple detect is provided by an internal pull-up resistor.

Signal filtering is accomplished with a three-pole filter optimized for time and frequency response which provides 70dB of normal-mode-rejection at 60Hz. One pole of this filter is on the field side of the isolation barrier for anti-aliasing, and the other two are on the system side.

A special input circuit on the DI-8B47 module provides protection against accidental connection of power-line voltages up to 240VAC.

The modules are designed for installation in Class I, Division 2 hazardous locations and have a high level of immunity to environmental noise.