Electrical and DCS signals
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Which electrical signals can be transmitted to the DCS via communication? Which ones require a wired connection
The signals with which we are currently in contact in the electrical field include the operation signals of the main pumps, the control signals of frequency converters, and the display of the motor current for large-scale units; all of these are connected using signal wires. I wonder what kind of signals you use? Also, is it convenient to generate AO and DO signals electrically?
For the condition monitoring signals of pumps, such as current signals and speed signals, communication methods can be used if they are merely for indication; otherwise, hard wiring is required.
As I understand it, the principle should be: things that are not important, such as display, can be handled through communication； An important point is that, for things related to start/stop and control, hard wiring should be used. It is also necessary to consider whether electrical power can be output via a hard wire.
Additionally, care must be taken to isolate the exchange of electrical and instrumentation signals, especially for digital signals. The selection of relay power is very important in order to prevent interference from high voltages.
If communication is to be used, all signals can communicate with the DCS； Sometimes, to emphasize the importance of interlock signals, these signals can be connected directly via hard wiring to the MCC.
Simply put, there are two types. One method is to use hardwired connections for the chain connection and its pump stop buttons, while the other method is to use communication for the start/stop signals and the points that are not part of the chain connection. Such as pump start/stop feedback, current, etc.