How can the pipeline pressure signal be linked to an audible and visual alarm?
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We are currently upgrading our oil depot, and the automation system needs to enable real-time monitoring of the pressure signals from the 5 pipelines leading into the depot in the control room. Additionally, to ensure that when the pressure in one of these pipelines rises sharply and reaches the alarm threshold, an audible and visual alarm installed in the metering room will also trigger, indicating the name (or code) of that pipeline. Is this feasible? How to achieve it?
The normal monitoring circuit does not need to be modified; an additional DO signal can be added for audible and visual alarms at the site, and audible and visual alarms similar to those used in the auxiliary control panel can be employed.
It is possible to achieve the function you mentioned. First, connect the pressure signal to the secondary meter, and use the alarm output terminal of the secondary meter to control the on/off of the audio-visual alarm. It is possible to share one audible and visual alarm, or to have an alarm connected to each pressure channel; a wall-mounted instrument panel can accommodate all of these components.
1. DCS can be modified through configuration; real-time values can be monitored via the display screens, and alarms can be sent to speakers through modules； 2. Conventional instruments (transmitter + secondary display instrument) can be used for real-time monitoring, and the alarm output from the secondary instrument can be connected to a multi-channel audio-visual alarm device ；
The 4–20mA signal from the pressure transmitter is sent to an indicator with an alarm output, and the contact output signal from the indicator is then sent to a flash signal alarm for alerting. In Option 2, the signal from the transmitter is sent via a signal distributor to an indicator for pressure monitoring, and to an alarm setter at the same time; the contact output signal from the alarm setter is then sent to a flashing signal alarm for triggering an alert.
It is easy to achieve automated control: the pressure signal is collected by a pressure transmitter and sent to the DCS or PLC. A DO output provides 24V DC power to an explosion-proof audible and visual alarm device. Under normal conditions, the DO output of this alarm device is 0, meaning it is in the off state. In the control panel, it can be set so that when the pressure reaches its upper limit or when there is a significant change in the DV value, the audible and visual alarm is activated; at this point, the DO output becomes 1, meaning the alarm is turned on. The control system will also issue a warning indicating that the pressure is too high, and an alarm sound can be generated using speakers, so that both the site staff and those in the control room are aware of the pressure alarm. In total, only 5 voltage transformers and a 24V audio-visual alarm are required on site.