Transmitters, analog and digital

Until the introduction of transmitters, the raw measured values from temperature sensors reached control stations by cable. Once there, they were transformed and processed. This type of transfer had the disadvantage that the line resistance increased with the length of the cable, and thus falsified the measurement. This led to inaccurate measurement results. Today this form of transmission is only used in special cases, for example if the ambient temperature in the area of the sensor is too high, or if the place where it is installed is too narrow. These tasks can also be done via a transmitter to a carrier rail mounting in the control cabinet.

Head transmitters built into the connection head of the thermometer have become established in almost all other applications. One design often used for this purpose is a 2-wire transmitter, which draws its energy from its own connection cables. Their usual output current of 0 – 10V, 4 to 20 mA, and I²C corresponds to the measurement signal and is basically temperature linear. Both resistance thermometers and various types of thermocouples can be connected to the transmitter input.

Modern transmitters let you not only collect measurement values digitally, but also configure the devices. This involves, in addition to the selection of the sensor input and the measurement range, the storage of measurement point identifications such as MSR descriptions and TAG numbers, as well as the adaptation of the measurement signal using a specific sensor characteristic or an offset.

Another feature of modern temperature transmitters is their diagnostic functionality. The devices don’t just convert the value of the sensor into a signal suitable for processing. At the same time, they can check relevant parameters in the background, such as the internal electronics temperature, the supply voltage, and the lead resistance. If errors occur, the transmitter sends a corresponding signal, enabling among other things, the early detection of sensor breakages and short-circuits, supply-side effects, and when using dual sensors, the drifting of a measured value.

Whether analog or digital, our Profibus and HART-compatible head and rail transmitters provide the right solution for temperature measurements in process industries. In order to adapt them perfectly to your needs, we will program the transmitters according to your data. On request, we will issue you with a calibration certificate in accordance with EN 10204-2.1. Different versions are available for use in potentially explosive areas of application with the following approvals:

• ATEX
• NAMUR
• FM, CSA

Naturally, you can use our transmitters with inexpensive 2-wire connection technology not only for the resistance thermometers and thermocouples we manufacture, but also for sensors from other manufacturers.

Contact us for a tailor-made solution and benefit from our over 50 years of experience in the field of measurement technology. We guarantee customer proximity and short response times through our global sales network. Our fast air freight service ensures flawless, on-time deliveries.