Ametek Land Landmark Graphic AE, User Manual

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User Guide Signal Processor
LMG AE
3.4.1 Constant ranges for AET/AQT
The value of Constant A (H4) is -10 to +10 in increments of 1.
The value of Constant B (H5) is -10 to +20 in increments of 1.
The value of Constant C (H6) is -30 to +30 in increments of 1.
The value of Constant D (H7) is -30 to +30 in increments of 1.
All the constants are pre-set to the default value of 0, but they can be
individually selected and adjusted as required.
The constants A and B do not appear in the menu if ‘Calibration’ mode is
selected (see Fig. 25).
The values required for constants C and D will be printed on the information
label for the thermometer utilised, and should be set to match accordingly.
3.4.2 Explanation of Constants
Constant A (or processing parameter H4 ) has been included to allow for a user
trim, relative to a surface thermocouple reading in case of an unusual, highly
cavitated section which could produce a very high emissivity reading. This might
occur because of many inter-reflections within the internal walls of the section
and give rise to an unusual ‘balance’ in the effective emissivities at different
wavelengths.
During trials, added sections were encountered which gave rise to effective
emissivity values of up to 0.4, however, the instrument automatically coped
with these changes and no adjustment to H4 was necessary to maintain
measurement accuracy.
It is recommended that this parameter be left at the factory default setting
of 0 and only changed if errors are suspected on highly cavitated and
emissive sections.
Constant B (or processing parameter H5 ) has been included to allow a user trim
relative to a surface thermocouple reading for high magnesium content or other
unusual alloys.
NOTE
Increasing the value of H4 will decrease the processor indicated
temperature and vice versa.