5.1 Analyzer Module Setup

5.1.12 Differential Measurement

Main Menu — Analyzer and I/O-module expert configuration

↓

Analyzer module setup

↓[2nd menu page via F5 (More...)]

 

 

Differential measurement

 

 

 

↓

 

TAG

 

 

 

95.00 ppm

 

-- Differential Measurement --

 

Function is:

 

 

 

Disabled

Choose source channel...

 

 

Source concentration:

Use actual value

Store source concentration !

 

 

Source channel:

 

 

----

Measure

 

Channel

Back...

 

F1

F2

F3

F4

F5

In the menu "Differential Measurement" you can measure the difference between the current concentration and a reference concentration of the same gas component. That means, the measurement value is not based on the zero value as it is usual for an absolute value measurement. Instead of this the signal will be compared with defined concentration of the component selected. That may be useful for concentrations that only differ a little from the basic value of this component in the measurement environment (Example: CO2 of plant in air).

If you want to make a differential measurement for other components, you can change to the other channels of an MLT analyzer or analyzer module with the F3 key.

Condition:

¨You have to calibrate with zero gas and to linearize the measurement channel and the reference channel.

·To calibrate see 4.5 p. 4-39and 4.6 p. 4-43or 5.1.1 p. 5-15to 5-17.

·To linearize see 5.1.5 p. 5-33

Differential measurement:

1)Disable the function:

·Press the 8 -key or the → -key in the line "Function is" to select the parameter and adjust "Disabled" with the − -key or the ↓ -key. Confirm it with the 8 -key.

·This is necessary to avoid interference of values while the parameters where determined.

2)Select the reference channel:

·Change to the menu line "Choose source channel..." with the ↓ -key and press the

8 -key or the → -key to go to the submenu "Channels":

90003482(2) [NGA-e (MLT-Software 3.2.X)] 07/98

NGA 2000

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