The solenoid valve is not working properly
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In the company’s newly built PSA project, the solenoids used for the programmable valves are ASCO WSNF8551A321 two-position five-way types, and such a situation occurs. After the programmable valve is separated, if its on/off state is switched independently, the programmable valve operates normally ； After being installed in the system, after it runs automatically 2 to 3 times, the programmable valve can only be opened and not closed. The cylinder of the programmable valve has two air supply channels, one at the top and one at the bottom
If the solenoid valve works properly when not using the sequential control, and the problem only appears after sequential control is activated, could it be that the sequential control logic is stuck at some step?
You just need to determine whether the solenoid valve changes state when powered on or powered off Try it several times repeatedly; for a two-position five-way solenoid valve, there is one air inlet, two exhaust ports, and two air outlet ports
When it is not operating, check whether the programmable valve is receiving power; if it has power but still doesn’t operate, then there is a problem with the valve’s coil. If it has no power, then it’s a programming issue
It is possible to determine whether there is a problem by checking whether the solenoid valve is powered or not. Remove the solenoid valve and connect the air tube directly to the cylinder to determine if there is a problem with the cylinder. If everything else is fine, then it’s a control issue
The issue with the coil is easy to determine; what the original poster means is that such problems arise only after the sequential control system is activated. In PSA hydrogen production, the sequential control uses feedback from valves as a basis for making decisions. Another possibility is that there is a problem with the feedback, which prevents the subsequent steps from being carried out
That’s one reason; in case a problem arises, it’s possible to monitor the sequential control process to see which stage it has reached, thus gaining clarity
Just insert a screwdriver into the coil to find out, or check the diagram to locate the output points
Check whether the spool of the 2/5-way valve is stuck, whether the air path is functioning properly, and also see if the valve itself is stuck
First, it’s normal after being cut out. This indicates that both the solenoid valve and the (actuator) should be fine. After it is put into use, it will take two or three times before a failure occurs. The logic explanation is also fine. The problem must lie in the feedback signal. Is there a poor connection somewhere?
Try using the substitution method to see which issue it is