Setting The Emissivity - Ametek Land Fibroptic FG User Manual

Fibroptic Model FG Thermometer
To test the unit:
1) Ensure that the thermometer is connected in a 4 to 20mA loop as shown in
Section 5.0.
2) Unscrew the four screws in the lid of the processor and remove the lid.
3) Refer to Fig. 6-1. Set the switch marked SIG/TEST to the TEST position.
4) Check that the temperature indicating equipment's display reads 1275°C
±3°C/2325°F ±5°F.
5) Set the switch marked SIG/TEST to the SIG position.
6) Replace the lid and tighten the four screws in the lid.
If the temperature display was not 1275°C ±3°C/2325°F ±5°F, check all the
electrical connections and repeat the test.
If the test can not be completed satisfactorily, check each item of equipment
(i.e. Power Supply, Indicator, Model FG Thermometer etc.). If the thermometer is
found to be faulty, contact Land Instruments International to arrange for repair.

6.3 Setting the Emissivity

To set the emissivity on a Model FG thermometer, the two emissivity pots (see
Fig. 6-1) on the main PCB should be manually set to correspond with the calcu-
lated emissivity value of the thermometer target. Refer to the emissivity tables
in Section 6.4.
To set an emissivity value:
1) Unscrew the four screws in the lid of the processor and remove the lid.
2) The factory default emissivity setting is 1.00. This is shown with each pot
set to '0'. To change the value, set each pot value accordingly (looking at
the pots with the '0' uppermost).
ie. for a required value of :
3) Replace the processor lid and secure the four screws.
IMPORTANT NOTE
Interchangeability with 'Original' Model FG units
'Original' Model FG thermometers are permanently set, by default, to an
emissivity value of 1.00.
Units of Model FG with emissivity adjustment should therefore be set to
1.00 for optimum interchangeability with units of 'original' Model FG.
Page 12
0.73 - left pot set to 7, right pot set to 3
0.91 - left pot set to 9, right pot set to 1
User Guide