Regarding DCS communication
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There are various protocols for communication between DCS systems, and our company primarily uses DP. I would like to know how exactly it is connected to the main controller using DP communication I’m working on the layout for the statistical control system. Should I reserve a slot for each signal that is transmitted over the communication link, or can they all be connected in series? I didn’t quite understand the information regarding the communication protocols found online: dizzy:
If you take a look at how the specific DP connectors are made, you’ll understand. DP connectors can be connected in series, but it’s necessary to consider how many components will be affected if a connection is broken; therefore, whether to use series or parallel connection depends on the overall design.
Many devices can be connected to one bus, but you also need to consider the data traffic volume; with too many devices, the polling time increases. It’s better to use multiple buses.
If you are talking about communication between DCS systems, for example, if you have multiple DCS systems and need them to communicate with each other, then one of the DCS systems must be set as the master station while the others serve as slave stations. For this type of communication, a DP communication module needs to be installed on the master station; the same principle applies when communicating between a DCS system and other control systems such as PLCs. Both the master station and the slave stations require DP communication cards, which are connected to each other using DP cables, after the addresses have been set. There is another scenario in which there is only one DCS system, with the rest being remote stations that lack CPUs and consist only of I/O modules; in such cases, DP cables can be used to connect the module bases together. I’m not sure which type you are referring to
It’s the communication between the plant’s main controller and the purchased control system that comes with it; it should be the first scenario
If that’s the case, then the configuration needs to be modified in both control systems. If it wasn’t designed this way initially, first, for the DCS part, the hardware configuration must be updated by adding a communication module. Second, for the other control system, check whether it has a DP communication module; if not, one must also be added. For Siemens PLCs, this usually isn’t necessary as they come with such modules by default. Once the hardware requirements are met, the next step is to modify the software configuration of both systems