Model NGA2000 HFID

Instruction Manual

748297-E June 2003

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 appropriate gas(es) will not correct the problem because 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.

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 INLET. 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 operation 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 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 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.

Rosemount Analytical Inc. A Division of Emerson Process Management

Startup and Operation 3-5