The current in the transmitter circuit is high
Thread Content
I would like to ask the teachers: the current in the transmitter circuit is greater than the output current of the transmitter, and this circuit is connected to a PLC channel.
That’s impossible; in the same circuit, how could the current values be different? ?
I don’t understand what kind of issue it is – is there a problem with the measuring instrument?
I don’t understand; in a circuit, the current is the same everywhere. The so-called transmitter output current is the one you measure directly when you disconnect the circuit (what do you use for power supply?) ) Or is it the result of your theoretical calculations (or what is displayed on the transmitter’s header?) ）
There are two scenarios: first, the value displayed on the instrument does not match the value shown by the PLC; second, the current value calculated based on the instrument’s display does not correspond to the actual measured current value. What exactly do you mean? I don’t understand. For the first option, just change the range – make it the same on both sides; that’s how it works, right? For the second option, try restoring the gauge to its factory settings; if it still doesn’t work, send it back to the manufacturer
The insulation between the return cables has deteriorated, causing leakage current. Although the voltage drop is not significant, 24V is sufficient to drive the transmitter; however, the current measured at the PLC side is the transmitter’s output plus the leakage current.
Measure the insulation resistance of the transmitter cable relative to ground, as well as between the two conductors.