Siemens SITRANS P DS III - Operation of the Electronics

Description
3.6 Principle of operation
SITRANS P DS III with PROFIBUS PA
Operating Instructions, 06/2013, A5E00053276-07
27
3.6.2
Operation of the electronics
Description
①
Measuring cell sensor
⑧
Buttons (local operation)
②
Measuring amplifier
⑨
Display
③
Analog-to-digital converter
⑩
Power supply
④
Microcontroller
⑪
DP/PA coupler or DP/PA link
⑤
Electrical isolation
⑫
Bus master
⑥
Each with an EEPROM in the measuring cell
and in the electronics
p
e
Input variable
⑦
PROFIBUS PA interface
Figure 3-6 Principle of operation of the electronics with PA communication
Function
● The inlet pressure is converted into an electrical signal by the sensor
①.
● This signal is amplified by the measuring amplifier
② and digitized in an analog-to-digital
converter
③.
● The digital signal is analyzed in a microcontroller
④ and corrected with regard to linearity
and thermal characteristics.
● The signal is available at an electrically isolated PA interface
⑦ on the PROFIBUS PA.