Design; Mode Of Operation - Siemens SITRANS TF2 Instrucciones De Servicio

Technical description
1.2

Design

The SITRANS TF2 has a stainless steel housing (∅80 mm) with protective glass. The
stainless steel protective tube with G½B or ½'' NPT threaded plug contains a Pt100
temperature sensor. The stainless steel used gives the protective tube a high level of
chemical durability, leading to a high degree of protection against external influences
for the temperature sensor.
The protective tube is available ex stock in the lengths of 170 mm or 260 mm. How-
ever, customized versions up to 2500 m are also possible. Additionally, the protective
tube can be provided in different materials on request.
The electric connection is on the back of the housing for the current supply via voltage
loop 4, 20 mA. The connection is established via a plug connection in accordance with
EN 175301-803A.
The 5-character display is on the front of the housing behind a glass cover. The 3 keys
for parameterizing the SITRANS TF2 are below the display. One green and one red
LED above the display indicate the operating status.
The SITRANS TF2 is available in 2 variants (see dimension drawing).
In the radial design (type A), the display is mounted parallel to the protective tube. The
display can be rotated by up to 120° opposite the protective tube.
In the axial design (type B), the display is mounted at a right angle to the protective
tube. The display can be rotated by up to 360° opposite the protective tube.
1.3

Mode of operation

The outside Pt100 temperature sensor is supplied with current via the constant cur-
rent source lk. This creates a voltage drop that corresponds to the temperature via the
sensor. The voltage drop is converted into a digital signal in the analog digital con-
verter (A/D).
In the microcontroller (µC) the signal is linearized and is evaluated according to the
data stored in the EEPROM.
The transmitter can be subdivided into the following function blocks and individual
functions:
36
Operating instructions
SITRANS TF2
A5E00263328-02