What should be done if the sensors in the system cause the system to shut down as soon as they are grounded?
Thread Content
A PLC system has many sensors, right? Sensors for pressure and temperature, as well as various control valves, and it also has its own power supply. There’s a problem now: if the sensor gets accidentally grounded, the entire system shuts down. Is there any solution to this?
You can start by trying it at one point and installing a safety barrier to see if it works
You can start by trying it at one point and installing a safety barrier to see if it works
Ensure proper grounding protection; this type of grounding is an abnormal condition, so the system shutting down or restarting is a protective measure. The issue lies in the sensor’s grounding, not in the problem of shutdown itself
Power supply is separated; the power supply for the sensors is independent from the power supply used by the PLC. Check the PLC manual for specific details.
Actually, there are two possible reasons for this issue. First, it could be that there is a ground fault at the site, which causes a short circuit in the power supply and results in the entire power supply shutting down. This problem can be resolved by installing fuses; in such cases, only one circuit will be disconnected, rather than the entire power supply. Second, it might be that a certain sensor is critical and must not fail under any circumstances; if it does fail, it will trigger a system shutdown. For this issue, I think it’s possible to address it by using additional sensors, with one sensor in use and another as a backup. In this way, the system will only shut down when both sensors fail simultaneously, thereby reducing the likelihood of both sensors having a ground fault at the same time
The power supply for the sensor should be isolated, right? It is recommended to check the entire power supply circuit; specific situations require specific analysis.
The problem must lie with the sensor; as a bold hypothesis, it’s possible that the ground wire is connected to 0V