User guide

4 - 8
PN 074-566-P1B
Composer Elite Operating Manual
4.1.10 What Happens if the Reference Zero
is Improperly Set?
If the Reference Zero is set when the conditions are wrong, i.e., not completely
purged of precursor gas:
1 A permanent concentration offset is introduced equal to the residual precursor
concentration when the new Reference Zero is applied. This is not corrected
until a proper Reference Zero is performed.
2 The sensitivity is altered, leading to an error proportional to the concentration.
Figure 4-6 Impact of wrong zero frequency
NOTE: Factory Zero will be restored if one of the carrier gas parameters
(molecular weight or ) is altered or if TEMP 1 Setpoint is changed or if
Allow User Zero is changed from Yes to No.
TMIn in H2: Impact Of Wrong Zero Frequency
-0.005
-0.025
-0.015
-0.035
0.0 2.01.51.00.5
True Concentration (mole-%)
Error (mole-%)
Zeroed at 10 Hz below
true carrier frequency
Zeroed at 20 Hz below
true carrier frequency