ÐаÑалог Weidmuller: Electronics - Analogue Signal Conditioning
ÐаÑалог Weidmuller: Electronics - Analogue Signal Conditioning
ÐаÑалог Weidmuller: Electronics - Analogue Signal Conditioning
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EX basics<br />
Technical appendix/Glossary<br />
In which operations are ATEX-certified electronic devices<br />
(such as signal converters, isolation amplifier, Namur<br />
switches and switching amplifiers) used<br />
ATEX-certified devices are used within industrial facilities and<br />
production halls where there is the possibility that explosive<br />
gases or dusts may be released.<br />
Transportation and production applications which require the<br />
use of such certified devices are listed below:<br />
• Off-shore oil and gas drilling<br />
• Tanker ships which carry oil, gas or chemicals<br />
• Ships which carry potentially explosive materials<br />
• Refineries and other oil or gas production plants<br />
• Transportation and filling stations for oil and gas<br />
• Petro-chemicals<br />
What are the differences between standard devices and<br />
intrinsically safe devices<br />
For electronic devices that are being used in Zone 0(20) or<br />
1(21), none of the components or electrical circuitry are permitted<br />
to generate unallowable high temperatures or sparks,<br />
whether during normal operations or during malfunctions. In<br />
other words: "All of the circuits in intrinsically safe electrical<br />
devices (Ex i) are safe and are not capable of igniting explosive<br />
atmospheres“.<br />
What is the device category<br />
The device Group II (hazardous areas not including underground or above-ground mining operations) is divided into device categories<br />
1, 2 and 3. They have the following safety levels:<br />
Surroundings Device category Occurrence and duration of explosive<br />
atmosphere<br />
Group II 1 Constantly occurring<br />
Long-term<br />
Regularly<br />
Group II 2 Occurrence probable<br />
over a limited time period<br />
Group II 3 Occurrence improbable<br />
Only for short periods<br />
Ignitable materials<br />
Gases, vapours, mist, dust<br />
Gases, vapours, mist, dust<br />
Gases, vapours, mist, dust<br />
Safety levels<br />
Permitted errors<br />
Groups and zones<br />
Comparison<br />
Very high safety level<br />
Group II<br />
2 different protection classes Zone 0 (gas)<br />
or<br />
Zone 20 (dust)<br />
2 independent errors<br />
High safety level<br />
Group II<br />
1 protection class<br />
Zone 1 (gas)<br />
For which no more than one error may occur Zone 21 (dust)<br />
Normal l safety level<br />
Group II<br />
Required protective measures Zone 2 (gas)<br />
Zone 22 (dust)<br />
W<br />
W.13
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