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Showing results for tags 'analog input problems'.
Working on a project with several UIA-0800A analog input modules. We are using all 4-20 ma transducer input. Pressure, Flow, Weight(load cell), pH. the only difference is for some of the transducers we power the loop thru and external power supply (24VDC) for the pressure transducers. results are solid. Others the loop power is provided by the transducer. For example for the Load cells the scale provides an 4-20 ma output signal with loop power to the UIA-0800A. What is very strange is the input signal floats around at a slow steady pace. including going below 4 ma. at first the number will appear solid then it will slowly drift down below 4ma down to zero and then will slowly climb back to a fairly accurate reading. It continually oscillates over a 1-3 min cycle. Very strange . My question is has anyone experienced this problem, and is there a minimum voltage required into the card. some of the loop power from the sensors are less than 24VDC more like 15 Any input is greatly appreciated FPM