How The Calomat 7 Works; Option Modules - Siemens SIPROCESS GA700 Operating Instructions Manual

4.6.2

How the CALOMAT 7 works

Overview
①
②
③
Figure 4-9
How it works/measuring principle
The measuring method is based on the different levels of thermal conductivity of gases.
CALOMAT 7 analyzer modules work with a micromechanically produced Si chip, the
measuring membrane of which is equipped with thin-film resistors.
The resistors contained in the membrane are regulated for constant temperature. The
amperage required fluctuates according to the thermal conductivity of the sample gas. This
raw value determined in this way is processed further electronically to calculate the gas
concentration.
The sensor is in a thermostatically controlled stainless steel enclosure in order to suppress
the effect of the ambient temperature. To rule out flow influences, the sensor is mounted in a
bore hole next to the flow channel.
4.7

Option modules

Option module 1.1
Option module 1.1 (OM1.1) provides eight additional digital inputs and twelve additional
digital outputs. Because the module is a "passive" module, the processing unit is in charge of
controlling the OM.
Wall-mounted device
Operating Instructions, 05/2018, A5E31930403-06
Sample gas inlet
Measuring membrane with
thin-film resistors
Sample gas outlet
Principle of operation of CALOMAT 7
Description
4.7 Option modules
33