Technical Description; Range Of Application; Operation Principle - Siemens SITRANS TF 7NG313 Serie Betriebsanleitung

Instruction Manual
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Technical Description

Figure 2 Transmitter for temperature SITRANS TF
3.1

Range of Application

The transmitter SITRANS TF transmits the signal of resistance thermometers, resistance based sensors,
thermocouples or voltage sensors into an impressed direct current that corresponds to the sensor
characteristics.
The SITRANS TF with built-in SITRANS TK-H is capable of communication (HARTR protocol V 5.7). It
enables a parameterization with PC or HART communicator (Hand-Held communicator).
The transmitter SITRANS TF with built-in SITRANS TK is parameterised with a PC.
Transmitters belonging to the "Type of protection: Non incendive" type can be installed in explosion hazard
areas (Zone 2).
Transmitters of type "Intrinsically safe type of protection" can be installed in explosion hazard areas
(zone 1).
Transmitters of type "Flame-proof enclosure" can be installed in explosion hazard areas (zone 1).
3.2

Operation Principle

The measured signal supplied by a resistance-based sensor (2, 3 or 4-wire connection) or by a thermo-
couple is amplified in the input stage. The voltage, which is proportional to the input quantity, is then con-
verted to digital signals in an analog/digital converter (1). Via electrical isolation (2), these signals are for-
warded to the microprocessor. In the microprocessor (3) they are converted in accordance with the sensor
characteristic and further parameters (attenuation, ambient temperature etc.).
The signal prepared in this way is converted in a digital/analog converter (4) to an impressed direct current
of 4 to 20 mA. The auxiliary power source is located in the output signal circuit.
The transmitter is parameterised with a PC (6) that is connected to the two-wire line via the modem (HART
modem) (7). A HART communicator can also be used for this purpose. The signals needed for communica-
tion in conformity with the HART
with the frequency shift keying (FSK) method.
A5E00046014-07
â
protocol V 5.7 are superimposed on the output current in accordance
SITRANS TF
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