Wiring issues with the emergency stop button and emergency shut-off valve
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Gentlemen, I would like to ask: there is a master emergency stop button in the main control room, another master emergency stop button on site, and also emergency stop buttons for each individual pipeline. How are the emergency stop button and the emergency shut-off valve wired? Are the emergency stop buttons from different locations all connected to the emergency shut-off valve? A total of 9 emergency shut-off valves. There are no PLCs or DCS.
Electric valve or pneumatic valve? Electric valves have a control box, while pneumatic valves have a solenoid valve box, right?
It depends on where your equipment is installed; for example, where will the 220V or 24V power supply come from? Is the cut-off valve interlocked when powered or when de-energized? Where are the individual emergency stop buttons? Theoretically, the main emergency stop button in the control room is installed on the live wire or the 24V+ main circuit; the local emergency stop button is also placed there, with the two being connected in series. It’s also possible to install the local emergency stop button on the neutral wire or the 24V- line, but this is generally not done as it violates the regulations. Nine branches are connected in parallel, with a branch-specific emergency stop button connected in series to each branch. But since there’s no PLC or DCS, I’m wondering how those valves can be controlled – you need to explain that
Like electrical power distribution? Are the two main parking buttons connected in series to the main circuit? Is it connected directly to a single valve? How is there no control system?
There’s no need for a DCS; even a PLC doesn’t cost much. Without such an investment, how can your company pass the audits?
The shut-off valve can be purchased as one that automatically shuts off under certain monitoring conditions, as well as in the event of a power or gas outage; thereafter, your emergency shut-off button can simply be connected to the power-off switch, so that it triggers automatic shutdown when pressed.
In hardwired circuits, it’s actually the control power supply that is involved. It can be done by switching off the power supply cabinet that powers the valve; as for exactly how to do this, you’ll need to figure it out on your own.