Seeking advice on DCS remote transmission issues for magnetic flap level gauges
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Our plant’s propane storage tanks, which are horizontal tanks, use magnetic flap level gauges. Occasionally, the DCS liquid level rises or falls suddenly within a few seconds, after which the feed pipe’s interlock valve closes and the compressor is shut down. In fact, the actual liquid level inside the tank hasn’t changed. All storage tanks have experienced such situations.
This situation may be caused by a malfunction in the magnetic components of the magnetic flap level gauge or the remote sensor, resulting in unstable signals received by the DCS system. It is recommended to check the sensor and connection wires of the magnetic flap level gauge to determine if there is any damage, disconnection, or interference. At the same time, considering adding a redundant system for level monitoring can help prevent incorrect level signals resulting from a single failure. If the problem persists, it is recommended to contact the equipment manufacturer for professional inspection and maintenance. .
For this thing, just check it step by step. First, for such batch occurrences, it is necessary to check whether the same junction box and AI cards are being used. If so, open the junction box to see if there is water ingress and whether the terminal connections are loose; also test the AI cards, and it’s best to replace them. Next is a check of the individual gauge; verify whether the float is damaged or not. It’s advisable to replace it with a remote sensing rod from another brand for comparative testing. Next, check whether there are any strong electromagnetic interference sources in the vicinity, and make sure the shielding wires and ground wires are properly connected. This table can also be connected to another AI card for comparative observation.
Thank you. We’re checking things step by step right now; all the floats have been replaced. The gas supply has also been changed from gas-phase supply to liquid-phase supply. The next step is to carry out an electrical inspection. There’s no explanation for either the equipment or the electrical issues~ As soon as there’s a problem with the liquid level, it’s reported to the system via remote monitoring~ Then emergency calls are made, and we get reprimanded:(
Is there a problem with the level transmitter? The magnetic flap level transmitter relies on the closure of magnetic reed switches to change the resistance value in the circuit; the transmitter then converts this resistance value into a 4–20mA signal, which corresponds to the liquid level. Is the remote signal a 4-20mA signal? If so, its resistance to interference is very high, and it’s impossible for interference to affect the signal on a second-by-second basis
Why are equipment and electrical issues being investigated? Doesn’t your factory have professionals in instrumentation? It’s hard to judge without being on site; let’s check things step by step. First, deal with the cable shielding and grounding, starting from the simple tasks and moving on to the more complex ones
Seeking advice on DCS remote transmission issues for magnetic flap level gauges
Let professionals handle professional tasks; adding a delay mechanism to prevent accidental actions is the best choice
It’s most likely a problem with the reed switch; there could also be signal interference!
Use a TON delay of 2 or 3 seconds; it’s fine to respond with a delay of 2 or 3 seconds if an accident actually occurs, but this approach can help avoid many interference signals.
There are problems with everything; the meteorological balance needs to be taken into consideration, as well as whether the connection diameter of the magnetic flap selected is appropriate. Additionally, signal filtering can be considered.