Bit_Bucket_07
Member
I was called into a plant recently to diagnose errors with their natural gas totalization. Long story short: They had installed orifice plate differential pressure meters and didn't understand that they needed to extract a square root value from the analog input from these transmitters in order to infer flow.
So, I fixed the problem and their rates and totalizations are now working correctly. I received a call this morning asking if I could help them to decipher months of recorded totalization values that they had accumulated when they were treating the DP input as though it was a linear flow value. The totalizers were being trended on an HMI, so they have this data available to them, but they don't know how to correct for the errors in the data.
I am going to work on trying to figure this out for myself, but I was hoping that someone here might have a solution that they could share with me before I manage to come up with a conversion formula on my own.
Two of the DP transmitters measure 0 to 250 inches of water, with 250 inches of water equaling 3000 SCFM of gas flow. The other meter is upstream of these two meters and measures the gas flow to both of the downstream meters. It measures 0 to 500 inches of water with 500 inches of water equaling 6000 SCFM of gas flow. Although the meters measure flow in SCFM, the HMI displays that value as SCFH, and the totalizations are done as SCFH.
Any help would be greatly appreciated.
So, I fixed the problem and their rates and totalizations are now working correctly. I received a call this morning asking if I could help them to decipher months of recorded totalization values that they had accumulated when they were treating the DP input as though it was a linear flow value. The totalizers were being trended on an HMI, so they have this data available to them, but they don't know how to correct for the errors in the data.
I am going to work on trying to figure this out for myself, but I was hoping that someone here might have a solution that they could share with me before I manage to come up with a conversion formula on my own.
Two of the DP transmitters measure 0 to 250 inches of water, with 250 inches of water equaling 3000 SCFM of gas flow. The other meter is upstream of these two meters and measures the gas flow to both of the downstream meters. It measures 0 to 500 inches of water with 500 inches of water equaling 6000 SCFM of gas flow. Although the meters measure flow in SCFM, the HMI displays that value as SCFH, and the totalizations are done as SCFH.
Any help would be greatly appreciated.