Problems with Siemens radar level gauges
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Question: A Siemens radar level gauge is installed in the tank area. The signal current from the gauge at the site is 4.88 mA, and the DCS display shows 62%. When a signal generator is used to send a 4–20 mA signal to the gauge, the DCS display matches correctly; however, when the wire is connected directly to the gauge, the DCS display shows over 60%. I would like to ask the experts where the problem lies with this gauge
What does the gauge of the radar level gauge show?
The header shows 0.56, and the current detection value is 4.6 mA
I encountered this situation on site before; it was similar to your case. We checked many possible causes but couldn’t find anything wrong. Later, when we inspected the wiring, we found a point where the signal cable was reconnected inside the conduit (steel tube). At that connection point, the shielding wire was shorted, which caused the signals from the site and those transmitted over distance to not match. After replacing the wiring, the problem was resolved
If you connect a multimeter in series in the circuit, what is the current value measured? Based on your description, if there is no safety barrier in the circuit, it seems that the possibility of interference is relatively high. The cable shielding ground must be properly connected.
The problem has been resolved; it was a ground fault in one of the circuit wires that caused issues with the signal along the entire main cable. Thank you to all the helpful friends. Thank you