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electronics, which is indicated on the display and converted into a 4 to 20 mA
signal which is transmitted to the controller. The refresh rate of the measured
values in the display and of the 4 to 20 mA signal is 80 ms.
3.2
Intended use
The PEX 1000 transmitter is intended to be used for the stationary, continuous
monitoring of mixtures of combustible gases and vapours with air under
atmospheric conditions. The full scale value is 100% or 10% of the lower
explosion limit (LEL). The transmitter is connected to a suitable controller by
means of a 3-core-cable, the measured signal during normal operation is
between 3.8 and 20.5 mA.
The PEX 1000 is intended to operate a remote Dräger sensing head.
Dräger sensing head
Polytron SE Ex PR M1 DQ
Polytron SE Ex PR M2 DQ
Polytron SE Ex LC M1 DD
Polytron SE Ex LC M2 DD
Polytron SE Ex PR NPT1 DQ
Polytron SE Ex HT M DQ
The PEX 1000 is approved for an ambient temperature range from -40 °C to
+65 °C. In conjunction with a suitable controller unit with preset alarm
thresholds acoustic or optical alarm devices can be activated or automatic
countermeasures can be initiated before the detected gases or vapours can
form dangerous flammable mixtures with air.
The PEX 1000 must operated in an earthed control cabinet when used in the
industrial sector.
3.3
Information for safe use
Only certified sensors or certified remote sensing heads are allowed to be
connected to the transmitter's br/br, ge/yw and sw/bk connection terminals.
22
Measuring range
Order number
100% LEL
6812711
100% LEL
6812710
10% LEL
6812722
10% LEL
6812721
100% LEL
6812800
100% LEL
6812720
Observe the following instructions for the measuring function:
1. The heat of reaction measuring principle, which is based on the catalytic
oxidation of a combustible gas, is essentially ambiguous because, at high
measuring gas concentrations, there is not enough oxygen in the sensor to
oxidise the combustible gas. As a result, the measured signal decreases at
high gas concentrations and can lead to values within the measuring range.
A connected controller unit must be operated with display devices,
measured value outputs (if available), and alarm thresholds operating self-
retaining if the measuring range is exceeded.
2. The heat of reaction measuring principle requires a minimum oxygen
concentration of 12 vol%, otherwise the displayed measured values will be
too low because of oxygen deficiency.
3.4
Measuring function for explosion protection
in acc. with 2014/34/EU and SI 2016/1107.
The PEX 1000 transmitter in combination with the sensing head Polytron SE Ex
PR ... DQ has been approved in respect to the measuring function for explosion
protection in acc. with EN 60079-29-1 for the following gases and vapours:
acetone, acetylene, ammonia, petrol 065/095 (FAM regular petrol), benzene,
1.3-butadiene, n-butane, n-butyl acetate, diethyl ether, dimethyl ether, acetic
acid, ethanol, ethene (ethylene), ethyl acetate, ethylene oxide, n-hexane,
methane, methanol, methyl ethyl ketone (MEK), methyl methacrylate, n-
nonane, n-octane, n-pentane, propane, i-propanol, propene (propylene),
propylene oxide, toluene, hydrogen and o-xylene.
The PEX 1000 transmitter in combination with the sensing head Polytron SE Ex
LC ... DD has been approved in respect to the measuring function for explosion
protection in acc. with EN 60079-29-1 for the following gases and vapours:
methane, propane, acetylene, benzene, ethene, n-nonane, propene and
hydrogen.
4
Control
4.1
Operate menu
The transmitter features a two-digit 7-segment display and two scroll keys (key
▲ and key ▼) to navigate through the described menus. Pressing both scroll
keys simultaneously equals pressing an OK button, indicated as "keys ( +▼)"
in the following. The ▼ key is also marked with an M to indicate that you can
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