Communication issues between control systems
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I would like to ask the experts: Our factory uses ABB’s AC800F control system, while the compressor control system is equipped with SHENGU’s ITCC. Since the distance between the control rooms is around 200 meters, we now want to establish communication between them. Could anyone please advise on how this can be achieved?
The compressor control system can serve as a branch of the DCS and communicate via the DCS’ I/O bus; it is generally best to create a dedicated interface on the DCS bus.
The older ones use DDE communication, while the newer ones use OPC, right?
It seems that the control systems all have communication interfaces, allowing them to communicate with each other. However, the communication standards of different manufacturers may vary
Use OPC; it’s very versatile and works with most control systems.
OPC probably won’t work here; serial ports or fieldbuses will have to be used instead
Thanks to the development and maturity of communication technologies, achieving data exchange between heterogeneous systems is no longer a problem. However, the choice of communication method still requires careful consideration of your requirements: according to Honeywell, if there are control signals between the DCS and the ITCC, then it is necessary for the ITCC to communicate with the DCS control stations, and the appropriate communication protocol can be selected based on those available on-site, at the field bus level； If it is used merely for data collection in the upper-level system, then communication can be carried out directly with the DCS server or the operator station; Ethernet + OPC will suffice.
As mentioned on floor 8, if data reuse is required, OPC can be used for data acquisition； If it is for control purposes, a control bus must be used.
For this distance, RS485 can be used directly. The key is that the communication protocols of the two systems must be identical; it’s best if both use the MODBUS RTU protocol
Well, thank you all; the problem has been resolved. By leveraging the insights of my colleagues here, we used RS485 along with standard MODBUS for communication via optical cables. Simply use the compressor as a slave station, set the corresponding address, protocol, port, baud rate, etc., and then the DCS can read the data.