Do the IO points of the loading system PLC also need to be configured in the central control system’s IO list?
Thread Content
We are currently working on a loading arm system; there are over a dozen such arms at the site, each with its own independent PLC system. The control room is equipped with a DCS system that is used to monitor and control all the loading arms. Now, each flexible hose PLC has its own independent alarm interlock. Is it still necessary to count the PLC’s IO points when compiling the IO inventory in the DCS system? Also, what should be done regarding the alarm interlocks? Should all details be described in the DCS system, or is it sufficient to mention only the interlock signals coming from the PLC?
Should the control points of the flexible hose PLC also be displayed in the instrument index table?
IO relates to hardware; there are two approaches. In the first approach, the points with which communication is to take place are listed in an IO table along with the communication method, without specifying the signals connected to the PLC. In the second approach, the data that needs to be communicated is included in a separate communication point table. In either case, this information must be reflected in the DCS monitoring data table. Any hardware devices whose operation is controlled by signals from the DCS, as well as any alarms related to such devices, must be shown in the DCS interlock alarm table.