Electromagnetic flowmeter voltage series current
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The newly installed electromagnetic flowmeter operates at a voltage of 220VAC. When connected to the PLC via wiring, there is an alternating voltage of over 100 volts at the pulse output and current HART output terminals, which affects all of the PLC’s analog channels. This results in inaccurate data and may even damage those analog channels. What could be causing this issue? Is it a problem with the PLC or with the instrument itself? I hope to get help and answers from fellow sea lovers!
If this occurs, please check whether the shielding of the signal cable is properly grounded at a single point; if that doesn’t work, add an isolation barrier
You’re combining the power cable and the instrument signal cable in one main cable
First approach to troubleshooting instruments: the elimination method. First, rule out issues with the instrument itself by checking the voltage at the instrument on site to see if there is any voltage drop ； Then check the cable shielding and various grounding points (including the grounding of the instrument’s enclosure, the grounding of the cable shielding, and the intermediate junction box) to see if there are any issues ； Finally, disconnect the instrument cable to check for any back voltage on the PLC side.
Are the power cable and signal cable routed separately? The wire with a voltage of over 100 is likely damaged. . Check the wiring and cables.
The Rosemount 8750W electromagnetic flowmeter uses a 220VAC power supply, and the wiring methods for the AI signal differ between active and passive configurations; I’m not sure if this information is helpful for your question.
Is the electromagnetic flowmeter properly grounded?