- What is a carbon filter and why do I need one?
-
A carbon (or charcoal) filter reduces the quantity of non-methane hydrocarbons in the gas stream, which
ensures a more accurate methane level reading.
- What is a water trap and why do I need one?
-
The water trap is a filter that removes water from your gas stream. Without this, moisture
could be drawn into the body of your GEM where it can do permanent, or at least very
expensive, damage.
If you are using a charcoal absorber filter, the water trap should come before the charcoal
absorber. That is, the charcoal filter should be closer to the instrument.
- What is a particulate filter and why do I need one?
-
A particulate filter removes small particles—dust, pollen and so forth—from the gas stream.
This is important because particles degrade the instrument's performance and must eventually
be cleaned out during servicing.
The particulate filter is inside the GEM-2000 body, in the back behind the circular door with the large slot in it.
The door can be opened with a quarter or something similar. Slide the quarter into the slot and
turn counter clockwise.
The particulate filter should be checked regularly, at least every three months, and replaced immediately if it is clogged.
- How do temperature extremes affect my readings and instrument? What can I do to work in extreme temperatures?
-
Above 104°F (40°C) or below freezing, 32°F (0°C), your readings may be
incorrect, or the instrument may otherwise malfunction. In extreme heat, the GEM-2000 screen
goes black.
If you are working in sub-freezing temperatures, you can use a hand warmer to keep the instrument
warm. You might also keep the instrument inside your coat.
In extreme heat, try to keep the instrument out of the direct sun. If its readings become erratic or
the screen goes black, bring it into a cooler environment, such as your air-conditioned truck.
- Why is my methane reading so high?
-
You probably have other hydrocarbons in your gas. The
methane detector is sensitive to all hydrocarbons, so the presence of ethane, propane, butane and others
in your gas stream will cause your methane reading to be too high.
LANDTEC sells "Charcoal Absorber Filters (1-00000-5084)", which will reduce the contamination from
non-methane hydrocarbons.
For more information, see section 4.6 "Cross Gas Effects" on page 11 of the GEM-2000 manual.
- Why are my readings erratic? My Methane reading is rising and falling for no apparent reason.
-
Readings, especially Methane, can be affected by cell phones. Do not use your cell phone while you are taking
field readings.
- What is a "cross-gas" effect?
-
Some gas sensors are sensitive to more than one type of gas. Methane sensors, for example,
measure hydro-carbon bonds, which are present in all hydrocarbons, such as Ethane, Propane,
Butane and others. So, if these other gases are present, your GEM will read them as
Methane, and therefore report more Methane than is actually present.
Because landfills are known to contain large
amounts of Methane, and don't normally contain these other hydrocarbons, this cross-gas
contamination is not usually a problem.
The Oxygen and Carbon Dioxide sensors in the GEM instruments are relatively free of
cross-gas effects.
The H2S and CO sensors in the gas pods and the GEM™2000 Plus do show some
cross-gas effects. The GEM™2000/GEM™2000 Plus manual has a cross-sensitivity table for these
sensors.
- After I installed DataField, I got two desktop icons: DataField CS and DataField Online. Which one do I use?
-
DataField OnLine is an online service that must be purchased separately from the instrument.
If you have not contracted for DataField Online (also called EnviroComp), then you can ignore
or delete the "DataField OnLine" icon. The icon itself is simply an Internet shortcut to
the EnviroComp site hosted at LANDTEC.
DataField CS is software that runs on your own computer, and works without any additional
purchase. It allows you to create and manage Well ID lists, download field readings and
change settings. You cannot use your GEM-2000 without DataField CS.
- Is DataField CS compatible with Windows XP?
-
Yes. DataField CS runs properly on Windows 98/ME/2000/XP.
- What are the System Requirements for DataField CS?
-
- Pentium III 500 MHz microprocessor or equal.
- 64 MB RAM.
- 120 MB of free hard disk space.
- CDROM drive.
- Windows 98 or later
These requirements were common on machines sold in 2000.
- How can I connect my GEM to my laptop? There is no plug that fits your cable.
-
The cable that lets your GEM communicate with your computer is normally plugged into a "Serial" port,
sometimes called an "RS232" port. Modern laptops often lack this port. In this case you need a
"Serial to USB" adapter cable in addition to the cable supplied with your GEM. That is, you will
plug your LANDTEC-supplied cable into the adapter cable, which is then plugged into a standard USB
port.
We use the Belkin F5U409, but any such cable will work.
Check Google for adapters
- I downloaded my readings, but the well IDs are corrupted (meaningless characters)?
-
The readings you have downloaded can't be fixed. The problem can be prevented in the future
by doing a cold start of the instrument. Instructions for doing a cold start are in section 2.9
of the GEM-2000 manual.
- I spent hours creating my well ID list in DataField CS, but now I can't find it on my computer anywhere. What happened?
-
The Well ID list you created in DataField CS was not automatically saved on your computer. To save a copy
on your computer so that it is available for uploading to an instrument later, create the list, then
click on the "Save File" button on the Well ID screen and choose a folder and filename that will
allow you to find it later.
If you created a Well ID list, then uploaded it to an instrument but did not save it on your computer,
you can recover it in DataField by going to the Well ID screen and clicking "Load from Instrument".
The list will be loaded into DataField, at which point you should click "Save File" as described above.
Your Well ID list needs to be saved to your computer only once.