Model NGA 2000 HFID

Instruction Manual

760004-A February 2002

1.Verify that correct zero and span calibra- tion gases are being used properly. If so, attempt to recalibrate according to in- structions at the beginning of Section 3-4, ensuring that the oven, sample and case temperatures and displayed measure- ment 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 Adjust- ment Limits.

3.Recalibrate the analyzer module accord- ing to instructions at the beginning of sec- tion 3.4, ensuring that oven, sample, and case temperatures and displayed meas- urement reading are stable before initiat- ing the calibration routine.

4.Enable Calibration Adjustment Limits in the Calibration Parameters menu.

NOTE

If the range selections straddle 725 ppm, CH4, the zero and span calibration for each range must be done separately.

3-5 ROUTINE OPERATION

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

Supply heated sample gas to SAMPLE IN- LET. Adjust external flow controller or throttle 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 Analyzer Module will now automatically and continuously 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 combination of settings on the FUEL, and AIR pressure regulators. Settings must be determined experimentally, but the curves in Figures 3-1 and 3-2 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 following from the Main Menu: Technical Configuration 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 prolonged shutdown, the Analyzer Module requires about one day's continuous operation to stabilize. For several days afterwards, calibrate daily. The frequency of subsequent calibrations can be reduced as experience dictates, consistent with the accuracy requirements of the particular application.

3-6 SAFETY SYSTEM

The HFID Analyzer Module safety system will not allow ignition or continuous burner function unless the following conditions are pres- ent:

•The internal purge gas pressure is at least 380 hPa - gauge (5.5 psig). (Monitor dis- play message, Purge Gas Pressure in Physical Measurements menu, for proper setting.)

•Flow rate for purge air in is at least

16 L/min. and case pressure is greater

Rosemount Analytical Inc. A Division of Emerson Process Management

Operation 3-5