H65.0.01.6C-04
Operating Manual GCO 100
page 3 of 8
2.3 Connections
1.
Interface:
Connect to optically isolated interface adapter
(accessory: GRS 3100, USB3100, ...)
2.
Sensor opening
The
mains socket
is located at the left side of the instrument
2.4 Generals of CO-measuring
Carbon monoxide (CO) is combustible and highly toxic. It is invisible, taste- and odourless, the relative density is 0,97
(a bit lighter than air).
Already smallest concentrations can be dangerous for humans (depending of physical constitution)::
30ppm
Maxmum allowed working place concentration (MAK) for 8-hours of work per day
70..100ppm
Flue like symptoms after some hours: sniffing nose, headaches, excoriated eyes, short
breath
150...300ppm
medium exposure: dizziness, sleepiness and nausea, even vomiting
400ppm
extreme exposure: headache
800ppm
extreme exposure: headache, dizziness, nausea and limb twitching after 45min,
unconsciousness within 2h
1600ppm
headache, dizziness, nausea within 45min, death after 2 hours
CO is produced when burning carbon containing substances (Wood, coal, oil, petrol, gas, cigarettes...), especially
when not enough oxygen is available. In fresh uncontaminated air the CO-concentration is near zero. Transportation,
heating and industry exhausts are increasing CO concentrations in urban areas.
There could be measured CO also in the breath of smokers:
None smokers
<6ppm
Light smoker
6...10ppm
Smoker
10...20ppm
Strong smoker
>20ppm
Like with alcohol concentration in blood, also the CO is decomposed in the blood: around every 5h the CO content is
cut by half. Via the CO concentration of exhaled air, the saturation of the CO in blood haemoglobin can be derived.
The carboxy-haemoglobin in % can be displayed directly by the instrument: %COHb (p.r.t. Configuration of the
instrument). This value is an estimation of the carboxy-haemoglobin of blood via the exhaled breath.
The calculation above 5ppm is done according to: M.J. Jarvis, M. Belcher, C. Vessey and D.C.S. Hutchison, Low cost
carbon monoxide monitors in smoking assessment. Thorax 41 (1986), pp. 886-887
Procedure for the measuring of exhaled gas
We suggest to use the ESA-100 adapter and the T-piece (picture at right) in combination
with a suitable mouthpiece (accessories).
- switch on instrument, respectively reset the max-value by pressing Max key for 2 seconds
- inhale deeply and hold your breath 20 seconds, if possible (now CO migrates from the
blood to the air)
- exhale slowly and complete via the T-piece (preferably with mouthpiece)
- read the Maximum value by pressing the Max key shortly
If no T-piece is available, an estimation can done, by exhaling/blowing in the direction of the
sensor-opening at a distance of fewer than 5 cm.
Wait sufficiently between measurings to allow the sensor to dry and to degrade CO of the
previous measuring, if there was some.
3 Alarm functions
There are 3 possible settings for the alarm function: off (AL oFF), on with horn (AL on) and on without horn (AL no.So)
The alarm will be issued under the following circumstances:
- measuring value higher or equalling upper alarm limit ’AL.Hi’
- sensor error
- measuring values exceeding/falling below measuring ranges
- battery voltage too low or error in device (’Err.7’)
The alarm function is supported by the interface, thus, it can easily be monitored by a connected computer.
The acoustic alarm is depending of the value. It is an interrupting tone, increasing in intensity with the value, above
300ppm the tone is permanent.
Visual alarming: „AL.Hi“ flashes in the display
Additionally the exceeding of the MAK value is signalled with the MAK-arrow independently from the alarm settings.
Because the maximum workingplace concentration differ from country to country, this value is adjustable.