Thermo Channels ("Th1-4" Connections); Assemblies Of The Thermo Channels; Overview; Cold-Junction Compensation With A/D Converter - ETAS ES930.1 User Manual

ETAS
4

Thermo Channels ("TH1-4" Connections)

The ES930.1 is equipped with four mini-TC sockets ("TH1" to "TH4") for the con-
nection of thermocouples of type K.
4.1

Assemblies of the Thermo Channels

4.1.1

Overview

Cold
Junction
24 Bit A/D
Converter
Fig. 4-1
The four thermo channels "TH1" to "TH4" of the ES930.1 feature an identical
design. Each channel consists of the following assemblies (see block diagram
in Fig. 4-1 on page 29):
•

Cold-junction compensation with A/D converter

•

A/D converter

• Open TC Detection (Open Thermocouple Detection)
The functionality of all thermo channels can be configured separately.
4.1.2 Cold-junction Compensation with A/D Converter
The integrated Mini-TC sockets for connecting the thermocouples consist of
the same combination of materials as the thermocouples (NiCr and Ni) to
achieve high accuracies across the entire temperature range.
The ES930.1 uses a common cold-junction compensation for the four thermo
channels. Measuring the cold-junction is done together for all channels using a
PTC (PT1000) that is installed close to the material transition in the module.
The construction ensures that the measurement result is affected only by a few
tenths of a Kelvin, even in case of fast changes of the ambient temperature or
uneven temperature distribution.
The signal of the cold-junction compensation is digitized by an A/D converter
with a resolution of 24 bit and provided to the measurement unit.
4.1.3 A/D Converter
The A/D converters of the thermo channels have a resolution of 24 bit. The
maximum measuring range is -200 °C to +1372 °C and corresponds to the
measuring range of thermocouples of type K.
ES930.1 - User Guide
Thermo Channel n

. .
.
Thermo Channels "TH1" to "TH4"
Thermo Channels ("TH1-4" Connections)
24 Bit A/D
Converter
Open TC Diagnosis
Detection Unit
Measure-
ment
Unit
29