Siemens SITRANS P500, Operating Instructions Manual, Page: 75 / 238

Operate
6.2 Parameter description
SITRANS P500 with HART
Operating Instructions, 12/2014, A5E02344528-09
75
"1.1.7.1 Transfer Function"
In this sub-menu you can select the characteristic that represents the relationship between
the input pressure and the output flow.
The root charactreistics differ from each other by their specific behaviour below the root
application point. The root application point can be freely selected between 1 % and 15 % of
the output value.
"1.1.7.2 Squareroot Startingpoint" (Page 75)
You can select from the following characteristic types of the output flow:
Factory setting: srlin2
Setting range:
•
linear
• srlin
•
sroff
• srlin2
Purpose: Selection of the pressure-flow characteristic
Description: The parameter defines the characteristic of the output flow.
"linear" The output flow is proportional to the differential pressure.
"srlin" Up to the root application point, the output flow is proportional to
the differential pressure and thereafter it corresponds to the root
function.
"sroff" The output flow is 0 until the root application point, and thereafter it
corresponds to the root function.
A low flow cut-off.
"srlin2" The output flow is proportional to the flow, two-stage linear up to
the root application point. The first linear section ranges from the
zero point to 0.6% of the output value and 0.6% of the pressure
value. The second linear section runs with a higher gradient to the
root application point and then in accordance with the root function.
See also
Flow characteristic (Page 155)
"1.1.7.2 Squareroot Startingpoint"
Factory setting: 5 %
Setting range:
• Min 1 %
•
Max 15 %
Purpose: Setting the root application point
Description: The parameter defines as of when the standardised output value and hence
the output flow is output as the root function of standardised pressure.
Depending on the decision made under "1.1.7.1 Transfer Function"
(Page 75), this parameter is displayed or hidden.