Acousto-optic alarm signal
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I would like to ask everyone: Is the signal from the audible and visual alarm on the SIS system console represented by one DO? In other words, does one DO cause both the light to turn on and the sound to be emitted, and does it also cause the light to turn off and the sound to stop when reset? Does a mute button generally be provided in the SIS system? If it is to be set up, does that mean I need to buy an alarm with a noise-suppression function, one where the light and the sound are controlled separately, with 2 DOs?
The audio and visual alarm signals from the SIS (Safety Instrumented System) console can typically be implemented through a DO (Digital Output) signal. In this case, a DO signal controls both the audio and lighting alarms simultaneously. When an alarm is triggered, the light turns on along with sound, while when it is reset, the light goes out and the sound disappears. However, the mute button in SIS systems is a common feature that allows operators to turn off the sound after an alarm is triggered, while keeping the visual alarms active. In this case, you need to purchase an alarm with a noise-canceling function, so that the light and sound can be controlled separately. This usually requires two DO signals, one for controlling the lights and another for controlling the sound. In short, if you wish to implement audio-visual alarm and silencing functions in the SIS system, you need to purchase an alarm unit with silencing capabilities, and use two DO signals to control the lighting and sound separately. .
Two DOs, controlling the sound and light respectively； A DI that silences when pressed ； Once the interlock conditions return to normal and are reset (the reset is also a DI), the alarm light goes out as well.
It should be said that when the SIS DO is used to control the audio-visual equipment, a 24V DC supply is still required. 24V DC is used to activate the relay, thereby controlling the activation and deactivation of the sound and light circuit. For audio-visual systems powered by 220V AC, it is better to use a 24V relay to control the 220V relay, as this is a more reliable approach. I’ve seen on-site 24V DC relays used to control 220V circuits, and in such cases the relay often stays engaged and fails to turn off.
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