What is the principle behind using two solenoids in series within a shut-off valve in a SIS system?
Thread Content
What is the principle behind using two solenoids in series within a shut-off valve in a SIS system?
I’m a beginner; the design institute designed it this way, but I don’t understand why it needs to be connected in series. Could someone with more experience help me figure this out?
As long as one solenoid valve operates, it will trigger the interlock, thereby ensuring that an interlock function is not lost due to a fault in a solenoid valve when it is needed. However, when connected in series, the probability of malfunction is relatively high.
Used in applications with a lower SIL level. The DCS system controls one solenoid valve, and the SIS system controls one solenoid valve.
Are you referring to parallel connection, sir? If connected in series, will powering an electromagnetic valve ensure that the valve moves?
When a cut-off valve is connected in series with two solenoid valves, power must be supplied to both solenoid valves simultaneously for the valve to function properly!
Since it is in a SIS loop, and systems generally shut down in the event of a power loss, connecting those two solenoids in series provides 1oo2 redundancy, which offers high safety but relatively poor availability.
Bro, personally I think it’s better to have the two solenoids connected in parallel; that way, even if one of them fails, the other can still ensure normal operation； But the design institute designed it in series; I’ve never understood what the purpose of using a series connection is. Our factory site constitutes a major hazard source, with a SIL2 rating
The design institute explained to us that it is a safety-related connection, and our system level is SIL2. Personally, I think it’s important to take safety into account while also considering usability; an ASCO solenoid valve already costs 3,000–4,000, and here we have two of them in series – that’s too expensive, in my opinion