UEi Test Instruments CD200 - Manual (Page 3)

When the tic rate is initially set, (with no combustible gas being
detected), the bottom most (green) LED should be flashing on and off
rapidly. As the sensor moves closer to the source of a gas leak, the LED
indicators will light in sequence from bottom to top.
Setting the Alarm
The alarm functions independently of the tic rate. Use it to separate
significant leaks from background contamination. Slide the
Power/Alarm switch to the ALM position, and a warbling tone will
sound when a preset level of combustible gas is detected. The
thumb-wheel on the bottom of the instrument allows you to use
either the factory calibrated setting of .5% methane in air, or increase
the sensitivity to your own set-point.
To select the factory calibrated setting: turn the thumb-wheel
fully clockwise. You will feel a click when it reaches the end of its
motion and stop at this factory setting.
To increase the alarm’s sensitivity: turn the thumb-wheel
counter-clockwise. As the thumb-wheel moves out of the factory set
calibrated position you will feel a click.
To set your own alarm point:
1. In a controlled environment, create the circumstance you want
the alarm to report (a pinhole leak for example).
2. Allow your instrument to warm up for one minute in the
ALARM mode.
3. Move the sensor tip over the controlled leak.
4. Move the thumb-wheel slowly until the alarm sounds.
5. Move the sensor away from the leak to ensure the alarm stops.
6. Verify repeatability - Ensure the alarm sounds when the sensor
is returned to the leak source.
7. The instrument is ready for its application - Repeat these steps
if the thumb-wheel is moved.
The alarm mute button: located below the tic rate adjustment
knob, will silence the alarm as long as it is depressed. The alarm
lamp will continue to function with the alarm mute depressed.
The alarm will continue to sound for a short period after the probe
is removed from the leak source due to residual gas in the sensor
cavity. The duration of the alarm will be directly related to the
concentration of combustible gas the sensor was exposed to.
M a i n t e n a n c e
Cleaning
Use a damp cloth and mild soap to clean the case of your CD200. DO
NOT use harsh detergents or abrasives as these may harm the finish or
weaken the structure with an adverse chemical reaction.
Certain soaps are detected by the CD200. Check your sensitivity before
using any soap, and remove as much of the residual as possible with a
damp cloth.
DO NOT allow moisture to directly contact the sensor. Remove the
sensor tip guard prior to cleaning it. Rinse and dry thoroughly
before replacing.
I n s t r u c t i o n s
The CD200 runs through a one-minute warm-up and self-zeroing
sequence when it is first turned on in fresh air. During this warm-up
period the instrument typically responds by:
• Turn on the REA DY light - glows steadily
• Quickly increasing its tic rate, as though it were sensing a
combustible gas, then gradually returning to a slower tic rate
• Lighting the LED gas concentration indicators, which rise and fall
in concentration indicators, which rise and fall in convert with
the tic rate
Each time the instrument is put into service, you should conduct a
quick functional test. Simply expose the sensor to a known leak, like a
cigarette lighter, or pass the probe over a drop of combustible fluid.
After the initial warm-up, the instrument can be used to detect
combustible gasses. When the sensor in the probe tip detects a
combustible gas, the tic rate will increase and the LED gas
concentration indicators will begin to light. As the concentration of
gas increases so does the tic rate.
If the READY light is flashing, the batteries are low. They should be
replaced immediately. Low batteries will adversely affect the
instrument’s reliability. See the Maintenance section for
replacement procedures.
Use the alarm by sliding the Power/Alarm slide switch into the ALM
position. If the gas concentration reaches a preset level, the instrument
sounds a warbling tone while the ALARM light flashes.
If the situation calls for quiet operation, or if background noise makes it
difficult to hear the built-in speaker, you can use an earphone. The jack
is at the top of the instrument. Note that listening to the alarm or tic
through the earphone is very loud.
Adjusting the Tic Rate
The tic rate tells you when the sensor (in the tip of the instrument) is
getting close to a leaking gas. You can control the tic rate using the
rotary wheel in the center of the instrument.
A tic rate of 4 to 8 tics per second, in fresh air, is typical. As the sensor
comes near a combustible gas source, the tic rate increases. In order to
isolate the source of a leak, you may need to move the wheel counter
clockwise, decreasing the sensitivity, as the sensor moves closer.
The LED Indicators
There are a total of six LED indicators along the left side of the
instrument. Two green, two orange, and two red, which indicate the
relative concentration of gas detected. These respond in direct
proportion to the tic rate.
CD200-MAN P. 2
Move the wheel clockwise to
increase the frequency
Move the wheel counter-clockwise
to decrease the frequency