Is it normal for the output current of the flow meter to be low when measured with a multimeter, while the displayed value is normal?
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Several vortex flow meters in our plant show 13 m3/h on-site, while the DCS displays 12 m3/h. Using the hand controller 475 for communication, the output current comes out to 13 after conversion. I connected a multimeter in series to measure it, and the converted value was indeed 12. What’s going on here? The range is 0-80. I don’t see any errors in either the gauge or the DCS settings. I really don’t understand; I’d appreciate some advice from everyone. My skills in this area aren’t good enough, so please give me some guidance
There is one unit for which, although a multimeter shows 12 when connected in series, the DCS displays 13. I see that the range and output current settings in the instrument settings are the same; there seems to be no error
Firstly, milliampere signals weaken over long distances during transmission, and cable resistance also causes inaccuracies in the signal. You mentioned only a 1/80 change; you can conduct a loop test using the meter to see how much the control unit differs, and then adjust the 4-20ma output at the meter header to provide compensation
Take a look at your power supply modules and measure the gauge voltage to see if it is too low
The last edit to this post was made by 1111111 on 2019-3-12 at 13:02. 1. What you see with 475 is the theoretical value of the output current, not the actual value. 2. The value you read on the multimeter is the actual output current. 3. Based on this, it can be inferred that the output current of the instrument you are using has decreased – the amount of decrease is equal to 1÷80, which is 1.25% of the full scale. . . Therefore, the output current of the instrument needs to be recalibrated.
Finally, it was taken seriously – the explanation was excellent and easy to understand
Do I need to take the square root of the vortex street? Heard about it for the first time