Flow Rate Measurement (Only Differential Pressure); Diagnostic Functions; Overview - Siemens SITRANS P DS III Operating Instructions Manual

Operating functions through HART

7.20 Flow rate measurement (only differential pressure)

7.20 Flow rate measurement (only differential pressure)
Description
For the "Differential pressure and flow rate" device version, you can select the characteristic
curve of output current as follows without actuating the measuring mode selector:
● linear "lin": proportional to differential pressure
● square root extracting "sroff": proportional to flow rate, deactivated up to the application
point
● square root extracting "srlin": proportional to flow rate, linear up to the application point
● square root extracting "srlin2": proportional to flow rate, two-step linear up to the
application point
Variable application point
The output current for the "srlin" and "sroff" functions can be displayed linearly or set to zero
below the application point of the square root extracting characteristic curve.
Fixed application point
The "srlin2" function has a permanently defined application point of 10%. The range up to
this point contains two linear characteristic curve sections. The first section ranges from the
zero point to 0.6% of the output value and 0.6% of the pressure value. The second section
has a higher gradient and it goes up to the root application point at 10% of the output value
and 1% of the pressure value.
See also
Flow rate measurement (only differential pressure) (Page 96)
7.21

Diagnostic functions

7.21.1

Overview

Description
HART communication allows you to activate and evaluate a wide range of diagnostic
functions from a central control room or onsite:
● Calibration/service timer
● Min/max indicator
● Limit monitoring modules
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SITRANS P DS III with HART
Operating Instructions, 06/2013, A5E00047092-09