Thermocouple Sensor; Disconnection Detection; Compensating Cable; Thermo Electromotive Force - Honeywell TC4S User Manual

Isolated thermocouple input module

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The CPU module does not directly accept analog values. Therefore, analog value is

converted into a digital value before feeding to the CPU. In addition, the digital values

from the CPU must be converted back into analog values to provide an analog output.

Thermocouple sensor

A thermocouple is a sensor for measuring temperature. It consists of two dissimilar

metals, joined together at one end. When the junction of the two metals is heated or

cooled a voltage is produced that can be correlated back to the temperature. The

thermocouple alloys are commonly available as wire.

When a part of a compensating cable or thermocouple is disconnected, the Isolated

Thermocouple Input module detects the disconnection.

Cable to compensate the tolerance due to the distance between input thermocouple

terminal and thermocouple input module (temperature change) and in which both

terminals have similar thermo electromotive force between 90 and 150°C.

Thermo electromotive force for thermocouple temperature has non-linear characteristics.

Therefore, it processes the non-linear characteristics to linear in the module.

In a thermocouple sensor, the thermo electromotive force varies, depending on the

temperature of a part measuring electromotive force. Since, the thermo electromotive

force table of standards is based on 0°C, it compensates the gap between the current

temperature and the actual reference temperature (0°C).

R200

Isolated Thermocouple Input Module TC4S User's Guide

September 2010

Honeywell

1. Introduction

1.2. Terms and definitions

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