What is the reason why the liquid level rises instantaneously on the DCS?
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This post was last posted by Hadman on 2010-7-2 08:28 The editor asks for advice: I am using the Hollysys system. The liquid level has a differential pressure transmitter and a magnetic flip column liquid level gauge. On the DCS, I can see that the liquid level rises instantaneously and then returns to normal, but in fact it does not. How does this happen? The on-site device is interlocked, which will cause the machine to stop. Is there interference or other reasons? Is there a good way to solve this problem? Is it possible to delay the interlock for a while?
Does this happen for all liquid levels? !Or individually? A certain one?
This device only has five liquid levels, all of which have this phenomenon.
What measuring instruments are used for these five liquid levels?
It should be interference or grounding problem. It is recommended to find the problem and not change the chain.
If there is a problem with all five liquid levels, you can check whether the power supply of the card where the five liquid levels are located is stable to determine if there is interference from other lines. Then check the lines of the five liquid levels on site. Finally, sort out the lines between the site and the DCS to see if there are other power cables put together. It is recommended not to change the interlock, but if you really can't find the problem, you can also slightly modify the interlock. For example, you can delay the detection for 1 second and then add a fault detection delay (mainly for how long this phenomenon will occur). If the time is too long, there is nothing you can do.
I feel like this happens more often with magnetic flaps.* My company also has this problem. It was detected that the resistor inside the magnetic flap is broken.
First check the card distribution of the AI signals of the five liquid level gauges to rule out whether it is a problem with the system software and hardware.； Secondly, check the on-site installation wiring, line laying and shielding grounding of the five liquid level gauges to rule out whether it is caused by interference.