GE MOA 280i, Руководство по эксплуатации и обслуживанию

Страница: 67 / 211

GE Analytical Instruments ©2006 DLM 14291 Rev. A
6-7
A C C E P T N E W R E S P O N S E S
O L D P P M 0 . 1 2 1 5
N E W P P M 0 . 0 5 9 8
O L D P P B 0 . 2 4 3 1
N E W P P B 0 . 1 1 9 7
E N T a c c e p t C L R r e c e c t
C a l i b r a t i o n s a m p l e
h a s n o t b e e n s t a b l e .
E N T E R / C R L t o c o n t i n u e
C a l i b r a t i o n g a s c o n c .
l e s s t h a n z e r o g a s
c o n c . - c a l i b r a t i o n
c a n n o t b e p e r f o r m e d
E N T E R \ C L E A R c o n t i n u e
The ppm response factor should be in the range 0.09768 – 0.1465 and the ppb
response factor should be in the range 0.1953 – 0.293. If the calibration results are
outside of these limits, the display will indicate that the response factors are out
of range. In general, do not accept out of range response factors. To view the out
of range response factors, press ENTER (the response factors can be rejected by
pressing CLEAR in the Accept Responses Menu).
If the response factors exceed the recommended limits (ppm response >0.1465,
ppb response > 0.293), it usually means that the reaction cell is dirty or the frit
restrictor is partially clogged.
Chapter 14 contains a procedure for checking
the flow through the frit restrictor and cleaning
the reaction cell and frit. An out of range
message can also mean the flow of the NO
calibration gas is <200 mL/min, so that ambient
air is being drawn into the tee and the
concentration of NO reaching the detector is
less than the entered concentration. If the NO
standard is older than 12 months, then the
actual concentration of NO may be less than the
reported concentration resulting in response
factors that are too high. This can also occur
with brand-new regulators and NO cylinders.
Check to make sure that there is excess gas flowing out the open leg of the tee
and make sure the age of the gas standard has not exceeded the recommended
lifetime. For new regulators, allow the gas to flow for several minutes and repeat
the calibration.
A less common occurrence is getting response factors that are too low (ppb
response <0.195, ppm response <0.0977). This can occur if there is a light leak or
if the concentration of NO reaching the detector is greater than the entered
concentration. Make sure that the correct gas concentration was entered. Chapter
14 has a procedure for testing and correcting light leaks.
If the PMT signal is not stable during the calibration, an unstable calibration
warning will be displayed. This can be caused by too low of cal gas flow or loose