8.5
Free Measurement Test Procedure
Note:
The following description of the Free Measurement Test Procedure
assumes that the Limit Sets are applied and that gas readings are
required at both high and low engine revolutions. This may not be the
case in all circumstances. Since the Free Measurement Procedure is
highly flexible and is suitable for a variety of diagnostic purposes, the
description below should be considered to be a guideline only. An
experienced operator may, for instance, consider that to perform both a
high speed and a low speed test is, in certain cases, unnecessary in
view of the diagnostic purpose of the test.
To make gas measurements using the Free Measuring procedure:
•
Select the The Free Measurement Screen from the Gas
Analyser Menu (see 8.1 and 5.1).
•
Make any necessary amendments to the vehicle setup in the Free
Measurement Vehicle Setup Screen (see 8.2).
•
Allow the vehicle to come to normal operating temperature.
•
Insert the exhaust probe fully into the vehicle tail pipe.
Refer to the notes to 7.2: „Measurement Procedure‟ if the test vehicle
is equipped with twin tail pipes.
•
Select Limit Set 1 (see 8.1: „The Free Measurement Screen‟)
•
Accelerate the engine until the rpm reading falls within the Green
band of the Free Measurement Screen rpm indicator.
•
Maintain a steady engine speed and allow the gas readings to
stabilize (approx. 30 seconds).
•
Store the Limit Set 1 test results in data buffer 1 as described in
8.6: „Storing Data in the Data Buffers‟.
After the test data for Limit Set 1 has been stored Limit Set 2 will be
automatically selected and the “Toggle Limit Sets” button will show
Limit Set 2. The Green and Red indicator bands will change to
represent the Limit Set 2 values. The fact that data is now stored in
data buffer 1 will be confirmed by the appearance of the figure “1” in
the Free Measurement Screen toolbar.
•
Reduce the engine speed until the rpm indicator is between the upper
and lower limits specified for Limit Set 2, maintain a steady engine
speed and allow the gas readings to stabilize once more.
•
Store the Limit Set 2 test results in data buffer 2.
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