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

4.6.1

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.
Option module 2.1
The option module 2.1 (OM2.1) is a "passive" module whose control is handled by the relevant
analyzer module. For every component measured by the analyzer module, the OM2.1 makes an
analog output available. This option module also provides three digital outputs per analyzer
module with a fixed function assignment.
If the device is retrofitted with an option module 2.1, this must be activated via LUI or PDM.
Rack-mounted device
Operating Instructions, A5E31874006-12
Sample gas inlet
Measuring membrane with
thin-film resistors
Sample gas outlet
Principle of operation of CALOMAT 7
Description
4.7 Option modules
31