GDS
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Our company is currently using an old system for GDS, and we need to implement a logic for audio-visual alarms – any alarm should generate a digital signal that is sent to the audio-visual alarm system in the control room so that it can be displayed there. So, should we use flip-flops with reset priority or those with set priority? Or not use it?
It mainly depends on whether your audio and visual alarm is 1 or 0? Should safety considerations result in a 0-level alarm? That means reset takes priority.
This is not SIS; no inverse logic is required, normal logic is sufficient, which means 1 alarm. So, have you ever encountered a situation where the audible and visual alarms in the control room keep sounding until the concentration of oil, gas, or toxic gases decreases? Therefore, I added an AND logic in the middle, so that the alarm sounds and lights can be temporarily disabled. Because during this shutdown and purging, the plant area kept making noise non-stop.
This depends on the specific requirements; some organizations require that the system not be reset until the leak alarm has been addressed, in which case priority should be given to setting the alarm. Also, some units require that sound and light be separated; if the alarm does not stop, only the sound can be temporarily silenced, while the alarm light must remain on. Additionally, if it is a soft reset button, it is also necessary to consider whether it is a self-resetting button; this depends on the specific requirements of the company. Now, the importance of GDS is very high; it falls under the scope of safety and environmental supervision.
It depends on your specific situation. In the case of silencing an alarm, it should only mute the sound; the visual alarm should continue until the alarm condition returns to normal. It’s not possible to eliminate all the audio and visual alarms
GDS belongs to the broader category of SIS (Safety Instrumented Systems)
Do as you’re told regarding the design; otherwise, as long as it works is fine
Based on your logic, in normal situations involving emergencies such as safety issues, negative logic is used, which means reset takes priority.
GDS is a type of SIS; it is best to entrust the design to others.