Measuring Temperatures with Temperature Sensors TF - GALVATEK - #1

Particularly In surface treatment, the precise measurement and control of temperatures is of decisive importance for the subsequent quality of the treated items. To keep the tempera­ture of the liquid in storage tanks within the desired range, also prevents negative effects on the process liquids, such as freezing, crystallisation and excessive viscosity.

The following functions need to be implemented:

• Control of the temperature in order to automate process steps

(such as keeping the desired process temperature)

• Monitoring of the temperature

In order to avoid possible damage to the process, the process liquid (e.g. damage by excessive tempera­tures) and the tank (e.g. thermal damage)

With the aid of temperature sensors and suitable electronic units, you can control and monitor the temperature of liquids easily and cheaply.

Our temperature sensors are available In various versions:

• with rigid immersion tubes made of various materials

• with flexible tube made of Teflon-PFA

All versions can be equipped with one, two or three Pt 100 elements. Other temperature sensors specified by you can also be integrated.

The function of the temperature sen­sor results from the integrated Pt 100 sensor element. The temperature Is determined from the temperature-dependent change In the electrical resistance of the Pt 100 element. At 0°C, the element has a resistance of exactly 100Q. As the temperature Increases, the resistance of the ele­ment changes in direct proportion to the temperature change.

A suitable electronic unit generates a low, constant current through the Pt 100 element and measures the resulting voltage across the element. The resistance of the element, and thus its temperature, can then be determined with the aid of Ohm's Law (R=u/I).

The connection between the electro­nic unit and the Pt 100 element can be made with 2, 3 or 4 wires. We provide 4-wire connections because these permit compensation for the resistance of the connecting wires.

Temperature Sensor with Terminal Casing LC

The temperature sensors with a flexible tube made of Teflon-PFA (06.5mm) are extremely resistant to chemicals. They are also suitable for use In clean rooms and have no negative physiological effects. Their small size makes these temperature sensors suitable for use in plants and tanks where little space is available.

The PFA-tube is available in lengths up to 10m. The Pt100 sensor element, with an active measuring length of 50mm, is mounted to the end of the tube.

Particularly in the case of long wires, the wire resistance can have a con­siderable effect on the accuracy of the measurement. For this reason, you should always use 3-wire or 4-wire connections between the temperature sensor and the electronic unit!

The maximum wire length between the temperature sensor and the elec­tronic unit should not exceed 50m. For longer lengths, it is possible to connect a temperature transformer with a standard output signal of 4...20 mA between the two.