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BlurDavinci

Calculate Total flow out from Flowmeter

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Hi guys: I have a task on hand: A Filling process using Emerson Flowmeter which supply 4-20ma. I need to know how to calculate the amount of product flowing out from pipe. The process is as follow, Operator Set Target (In kilogram) ---> Start--->Valve Open--> Check for cumulative mass flow out of pipe, within tolerance--------> Stop. Process is simple If the Emerson module supply pulse. If it is in Analogue, how would l do it, using Time multiply with flowrate? That might not be correct. As the PLC Scan time might affect the accuracy. Am I right? Please give me some idea or guidance. Thanks

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Hi, Yes, you would need to integrate the curve. This should not be too difficult to implement using a time/multiply algorythm. You will need to consider if this method will give you resonable accuracy for your application, yes PLC scan time could affect accuracy if you need very fast sampling. Perhaps you could use timed interrupts? You could also use a third party 4-20mA to pulse converter - accuracy would depend on the quality of the device If high accuracy is important it would be best to connect flow transmitters pulse signal (I often connect both 4-20mA and the pulse to the PLC!) to the PLC as you suggest. This way, the accuracy of the total measured volume is as per the flow transmitters specification/accuracy. Nibroc Edited by Nibroc

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Perhaps you could use timed interrupts? If I have AB Contrologix! I never try on omron. Maybe I should take a look on cyclic Task. I'm looking around 20 to 50 gram accuracy. The hardware is installed, so no way to modified to pulse. I have not heard about " 4-20mA to pulse converter ", Nibroc, u used before? Can you recommend some? Thanks

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Hi, Weidmuller have a good range of signal converters, see .pdf from weidmuller catalog. I would however have a good try at writing some ladder code first. Nibroc 8461490000_MCZ_20CFC_204_20MA.pdf

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