Emerson Process Management NGA2000 HFID 用户手册

748297-E 

June 2003 

Rosemount Analytical Inc.    A Division of Emerson Process Management                                                                 Startup  and Operation    3-5 

Model NGA2000 HFID 

If the user is unable to calibrate the Analyzer 
Module (i.e., when ZERO or SPAN is initiated, 
nothing happens), several possible solutions 
present themselves. One solution relates to 
the use of an incorrect gas for zeroing or 
spanning (e.g., using a high concentration gas 
to zero or a zero gas to span the Analyzer 
Module). Simply recalibrating with the appro-
priate gas(es) will not correct the problem be-
cause the ZERO OFFSET or SPAN FACTOR 
has been set to an extreme value in the proc-
ess. 

To remedy the problem, do the following: 

1.  Verify that correct zero and span cali-

bration gases are being used properly. If 
so, attempt to recalibrate according to 
instructions at the beginning of Section 
3-4 on page 3-4, ensuring that the oven, 
sample and case temperatures and dis-
played measurement reading are stable 
before initiating the calibration routine. If 
incorrect gases were used in the initial, 
failed calibration, skip to Step 2. 

2.  Make the following selections from the 

Main Menu: Expert Controls and Setup, 
Analyzer Module Setup, then Calibration 
Parameters. Disable Calibration Ad-
justment Limits. 

3.  Recalibrate the analyzer module accord-

ing to instructions at the beginning of 
section 3-4 on page 3-4, ensuring that 
oven, sample, and case temperatures 
and displayed measurement reading are 
stable before initiating the calibration 
routine. 

4.  Enable Calibration Adjustment Limits in 

the Calibration Parameters menu. 

After case, oven, and sample temperature 
stabilization, calibration, and binding, proceed 
as follows: 

Supply heated sample gas to SAMPLE 
INLET. Adjust external flow controller or throt-
tle valve so that the sample inlet pressure is 
between 5 and 9 psig, 7 psig nominal. The 
reading on the SAMPLE pressure gauge and 
sample and oven temperatures should be the 
same as that used during adjustment of the 
zero and span calibration gas control. 

Adjust the Range Number setting. The Ana-
lyzer Module will now automatically and con-
tinuously output the measured hydrocarbon 
content of the sample. Output is in terms of 
the particular hydrocarbon present in the span 
gas. Note that readings obtained during op-
eration depend on the concentration of total 
hydrocarbons in the sample. 

If maximum sensitivity is required from the 
HFID Analyzer Module, use an optimum com-
bination of settings on the FUEL, and AIR 
pressure regulators. Settings must be deter-
mined experimentally, but the curves in Figure 
3-1 on page 3-7 and Figure 3-2 on page 3-7 
may be used as guides. 

The Analyzer Module will not allow the user to 
increase the upper limit of a range beyond the 
"maximum range" software setting. To change 
the "maximum range" value, select the follow-
ing from the Main Menu: Technical Configura-
tion Menu, Service Menus, Manufacturing 
Data, and Analyzer Module Data. Select 
Maximum Range, and use the arrow keys to 
scroll the indicated value. The same applies 
for Minimum Range settings. 

During shutdown, always turn off fuel gas first, 
then the air and sample gases. The flame can 
also be turned off by setting Ignition System 
Enable to "Off" in the Light Flame menu (un-
der Basic Controls). Subsequently, remember 
to set Ignition System Enable to "On" before 
attempting to ignite the flame. 

After initial startup, or startup following a pro-
longed shutdown, the Analyzer Module re-
quires about one day's continuous operation 
to stabilize. For several days afterwards, cali-
brate daily. The frequency of subsequent cali-
brations can be reduced as experience 
dictates, consistent with the accuracy re-
quirements of the particular application.