Wireless Temperature Measuring System with ATEX Approval and Electronic Modules up to 125°C

More versions have been added to Jumo’s (Germany) Wtrans temperature measuring system, taking into account diverse customer requests for products covering a wide variety of different areas of application. New to the product line is a transmitter with ATEX approval. Also new to the Wtrans family of products are transmitters containing a highly temperature-resistant electronics module, that can be used up to a temperature of 125°C .

Transmitters with ATEX approval can be put directly into a potentially explosive atmosphere. The receiver is mounted outside the actual EX zone. This means that cost-intensive installations with protective barriers and supply isolators are unnecessary. JUMO’s wireless technology shows a totally new approach here, and allows the customer to transmit temperature measurements across boundaries, out of the EX zone. The Wtrans transmitter can be located in Zone 0, right up to the process connection. In this example, the probe handle is in Zone 1. Of course, it is also possible to operate the entire instrument in Zone 1. Then, for the first time, it is
possible to regard a hazardous EX area as being completely disconnected from the “outside world”.

The transmitter is still located in the probe handle and is protected by a waterproof and dustproof housing. A blue plastic handle was chosen as an outward distinguishing feature. Instruments with a temperature resistance up to 125°C are used in applications where it is mandatory for the transmission electronics to be installed in the actual process. This is the case in continuous furnaces, for example, where the transmitters have to be in the product to measure, and they transmit their temperature data out of the hot zone. A gray plastic handle is the outward distinguishing feature here. There are versions that can be used to measure from –30 to +260°C with a fixed protection tube, as well as versions for a temperature range of –200 to +600°C with M12 connectors and a remote temperature sensor. It is the responsibility of the user to scale the particular output value and this can be individually adapted to the measurement task.

The rail-mounted receivers still make the measurement values available over four analog outputs (0[4] - 20 mA, 0 - 10 V) or two analog outputs and two floating relays, as well as over an RS-485 interface with a Modbus protocol. As many as 16 Wtrans transmitters can be managed over this interface for each receiver. Because Jumo’s forward-looking wireless transmission technology is used, there is a vast reduction in installation expenditure in all industrial applications. There are also other perfectly obvious advantages. In hard-wired systems, long connecting cables almost always hinder the user. Wireless-based temperature sensors provide effective and convenient alternatives compared to hard-wired systems, particularly at higher process temperatures.

There are no vulnerable, costly, cable connections and the wireless-based temperature sensor technology also works in a harsh, industrial environment, as well as in potentially explosive atmospheres. The costs for maintenance, repair and re-installation are also reduced, compared to hard-wired measurement data transmission. These developments open up totally new areas of application for user-friendly measurement value recording and transmission of temperature data. Further information can be found on the Internet at: www.jumo.net.