Assets

Resistance thermometer

SIEMENS measuring inserts are generally designed as a four-wire system for simple PT100. This makes it possible to implement all of the aforementioned connection types.

Double PT100 measuring inserts are designed as a three-wire system; four-wire systems are available on request.

Circuit diagram 1xPT100-2W - 2xPT100-4W

Thermocouples

Circuit diagram for thermocouple

Where thermocouples are used, the use of head transmitters offers particular advantages: The cold junction is already integrated into the universal transmitter. There is no need for expensive thermo or extension leads. This also removes a number of possible error sources. The weak millivolt signal of the thermocouple is already converted into a stable and temperature-linear DC or bus signal on site. This drastically reduces the effects of electromagnetic factors on the measurement result.

If a head transmitter is not installed, the sensor feed line consists either of the appropriate thermo or extension leads. The thermo line is made from the thermo material of the relevant thermocouple, while the extension lead uses a cost-effective substitute material. The extension lead behaves similar to a thermo line at an electrical level, within a limited temperature range of up to 200°C.

A wide spectrum of color coding is available for thermocouples on an international level. This must be taken into account during the connecting process.

¹⁾ With an intrinsically safe line as per IEC 584-3, the sheath is always blue.

^{2) For thermo lines as per ANSI MC96, the sheath is always blue.}

Transmitters

Where SITRANS TH transmitters are used in the connection head of the temperature sensor, connection takes place according to the following pattern

Resistance thermometer

Thermocouples intern cold junction

SITRANS TH100/TH200/TH300

SITRANS TH400

In addition, our transmitters also allow for a large number of other possible connections (e.g. difference, average, two sensors). More information can be obtained at: http://www.siemens.com/temperature