The automatic valve cannot operate automatically
Thread Content
Our company isn’t sure what’s going on; some of the automatic valves don’t function in automatic mode and have to be operated manually. They are controlled by a PLC, and it’s possible that the valve models chosen earlier were not appropriate. I would like to ask whether the fact that these valves cannot operate in automatic mode is related to the choice of valve models Is it still because the PID adjustment is not correct? Could that expert please explain it? Thank you in advance
This post was last edited by tiansf5936 on 2016-5-8 08:57. What I mean is, is the reason why my automatic penalty doesn’t work automatically a problem with the selection, or is it because the PLD isn’t properly adjusted? I personally think there should be no problem with the software
However, some valves can be automatic. Do you mean that this has nothing to do with the selection of the valve? Is it related to software? Is it related to this PLC as well? The refresh speed is indeed a bit slower compared to DCS
Selection is one aspect; the most important thing is that the PID parameters are not properly tuned
Do you mean our PLD isn’t adjusted properly? Do you think this is related to PLC? Does this have nothing to do with the selection?
Hehe, what on earth is an automatic valve? Is it a control valve? Whether automatic operation can be achieved depends entirely on the tuning of the PID parameters. To determine the appropriate choice, check the data sheet for the control valve; that should give you a good idea. Also, tell me what kind of circuit you have if automatic operation isn’t possible It is generally not possible to enable automatic operation in a single-loop system
There’s no issue with the circuit itself; the problem is that once the control valve is set to automatic mode, there are excessive fluctuations, which causes instability in the entire system. Do you mean that the PID settings are incorrect?
Yes, I think so. Try adjusting it again using the 4:1 ratio. Is your system a single-loop system, or is it of a cascade type? Generally, single-loop systems don’t experience fluctuations. What are your operating conditions like? Could the fluctuations be caused by those conditions?
1. Whether it can be operated automatically is one issue, and fluctuations caused by automatic operation is another. First, you need to determine whether it is the front or back side. 2. If automatic operation is not possible, check issues such as the PLC program and solenoid valves. 3. If there are fluctuations during operation, it depends on whether your medium and control parameters are related to level, temperature, or something else. 4. In a single-loop system, fluctuations generally do not occur; if fluctuations do appear, check whether there are any changes in the pressure within the pipeline network and whether the valves are stuck in place. 5. For the fluctuations in cascade control, what other parameters need to be considered? If it’s temperature, there is a lag, so differentiation is required. The fluctuations are too rapid; the ratio needs to be adjusted. You can research this