Questions regarding chain alarms
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Dear experts: The process interlocks related to flow rate, liquid level, etc., on a unit function normally. If the unit is out of operation for an extended period, alarms related to these interlocks (such as low liquid level alarms and low flow rate alarms) are considered normal alarms; the alarm control panel displays red, which may give the impression of insecurity to those without technical knowledge. Even after bypassing the interlock, the red display persists. Is it possible to change the set values of these interlocks or generate a fake signal to restore normal operation? But once that preset value for the chain is reached, it cannot be changed. What do you all think we should do? Thank you!
If the device is not in use for an extended period of time and no materials are stored there, the interlock can be disabled; the valves that need to be closed can simply be closed manually. The workshop should then go through the procedures to disable the interlock.
It needs to be clear whether interlocking gives priority to protective functions or to giving a good appearance to outsiders
During the period when the plant is shut down, there is no need to consider interlock-related requirements. When outsiders come for inspections, you can explain that the plant is shut down, and they won’t hold you accountable. If you’re obsessed about such things, then just deal with it; P;P;P
Actually, the bypass has been removed, but it still shows red and cannot be eliminated
Since it is interlock protection, safety interlocks must be ensured both during production and when the system is shut down. All interlocked disconnections must go through the relevant procedures. With interlock protection in place, process operators cannot arbitrarily start devices that are under interlock to cause accidents. As for the issue with the lights you mentioned, it is a technical problem; it is necessary to check the logical programs within the DCS/SIS system, or there may be hard interlock protections located not in the DCS/SIS but in the on-site control cabinets.
During parking, many parameters are already in the interlocked position; even with bypass interlocking, the interlocked status will be displayed due to the memory function, which is completely normal. This also informs the operators of the current actual situation to prevent accidental operations. If it is necessary to change these displays, the relevant procedures must be followed in accordance with the interlock removal regulations: everything must be removed first, and then reset.
Actually, there’s no need to change this; after all, the person who performs the shutdown inspection of the equipment can see it, and there should be no problems. It can also alert operators to prevent mistakes, thus avoiding other problems.
That makes a lot of sense; that’s how I explain it too!
There’s no need to handle it during the shutdown period