2/28/2014 3:29 PM | |
Joined: 1/2/2013 Last visit: 9/2/2024 Posts: 38 Rating: (4)
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Hello Nicer,Attached please find the part of our manual describing the values from the sensor cell through the pressure transducer block into the appropriate output values.The picture under 7.1.3 explains the differences between the values. At the first glance a scaling for PROFIBUS PA does not make any sense. Especially if you are measuring pressure and forward the pressure value to the control system. For a flow measurement this will be a different issue. The pressure value will be changed to 0…1 (0…100%). This value can be transformed into the flow value (dependence see attachment in my previous information). The working range can finally change the value to a flow unit.
AttachmentD:\Siemens\Support\Support allgemein\2014_02\Nicer Forum\DS3PAen_en-US[1].pdf (613 Downloads) |
3/5/2014 3:34 PM | |
Joined: 1/2/2013 Last visit: 9/2/2024 Posts: 38 Rating: (4)
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Hello Nicer, I have taken yourquestionand didsome tests and screenshots on my desk. I have chosen the following settings (The unit and range of the working range for flow has been chosen as an example. Any unit and range can be chosen. The percentage of the result will always be the same. For your tests you can choose any range and unit. For your real application you have to take the range and unit from the calculation of your pitot tube): Transmitter Type: Pressure Characteristic-Linear Measuring Range: 0 to 600mbar(secondary value 1 at the screen shot) Working Range: 0 to 600mbar (measured value at the screen shot) As you can see on my screen shot “Linear” the characteristic is linear. Measuring Range 50% at Working Range 50% Measuring Range 100% at Working Range 100% Transmitter Type: Flow Characteristic: Square Root Measuring Range: 0 to 600mbar Working Range: 0 to 600m3/h As you can see on my screen shot “Square Root” the dependence is square rooted. Differential Pressure 25% at Flow 50%Differential Pressure 100% at Flow 100% As you have already correctly stated in your thread “PRESSURE TO FLOW CONVERSION” a calculation will be required for your pitot tube. This calculation includes the data what flow will generate what differential pressure at the pitot tube. These values must be entered in your parameters. Please excuse the inaccuracy of my screen shots. I did that test with a hand pump so it was difficult to meet the exact values of 50% or 100%. AttachmentD:\Siemens\Support\Support allgemein\2014_02\Nicer Forum\Screen Shots.pdf (437 Downloads) |
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