Description
The TEMD is a screw-in temperature sensor in an intrinsically safe design, manufacturer type Müller METS-WTEx.
It is the Ex version of the series and is designed for installation in potentially explosive areas with gases. It is screwed directly into pipes, tanks, or units; the protective tube is made of stainless steel 1.4571, the system pressure is PN 25, and the protection class is at least IP 65. Compared to the other screw-in sensors in the series, it goes significantly higher in the medium: up to +425 °C.
It has no display, buttons, or limit contacts; the measured value is sent as a current or voltage signal for evaluation, and settings are made with the DEV-KMA configurator and TrComm software.
Measurements are taken with a Pt100 in a 2-wire circuit in Class A, B, or AA in the range of -50 … +425 °C with a minimum span of 50 °C. The output offers a choice between 4 … 20 mA in 2-wire technology and voltage signals such as 0 … 10 V in 3-wire technology. The accuracy is max. 0.1 % of the measuring range plus sensor error at 24-bit resolution, powered by 12 … 30 VDC.
Please note before ordering: The data sheet specifies installation for gases in Zone 0, Zone 1, and Zone 2 and lists three markings: II 1 G Ex ia IIC T6..T1 Ga, II 1/2 G Ex ia IIC T6..T1 Ga/Gb, and II 2 G Ex ia IIC T6..T1 Gb; it does not explicitly state which marking is assigned to which zone. The certifications are TÜV 21 ATEX 201293 X according to directive 2014/34/EU and IECEx TUN 21.0005X. Both approval numbers end in X, which means special conditions apply; these are found in the operating instructions and not in the data sheet. The temperature class is given as T6..T1, not as a single value; according to the data sheet, the applicable class depends on the installation. The ambient temperature depends on the output type: -20 … +75 °C is permissible for the 2-wire current output, but only -20 … +50 °C for the 3-wire voltage output – anyone who orders the voltage output and designs for the upper value will be 25 K too high. And the ambient temperature is not the medium temperature: The medium can be up to +425 °C, but the electronics in the head cannot – above +85 °C, they can be destroyed. A CE mark is not documented in the data sheet, and a declaration of conformity is not available. The version without explosion protection, with display and two limit contacts, is the TEMB (METS-WS).
Advantages at a Glance
- Intrinsically safe, marking II 1 G Ex ia IIC T6..T1 Ga
- ATEX TÜV 21 ATEX 201293 X and IECEx TUN 21.0005X
- Installation for gases in Zone 0, Zone 1, and Zone 2
- Pt100 in 2-wire circuit, medium -50 … +425 °C
- Accuracy max. 0.1 % of measuring range, 24-bit resolution
- 4 … 20 mA in 2-wire or 0 … 10 V in 3-wire technology