Still about OPC!
Thread Content
One system is HaliTech’s M6.5.2 DCS, and the other is AB’s PLC; these two systems are used to control different processes. Now, the customer wants all the data from the AB system to be transferred to HaliTech’s system, so as to enable monitoring and control. There is currently an OPC communication software in use, so monitoring should not be a problem. The number of communication points can reach up to 3,000. As for the AB side, the process is relatively complex, requiring precise control. From a feasibility standpoint, is it possible to use Allen-Bradley’s control AB system through OPC? If this can be achieved, what are the disadvantages? Thank you all, welcome to the discussion! I’m a newcomer; please give me some advice!
The Honeywell M6.5.2 DCS can achieve monitoring and control of the AB system through OPC, and there is no principle-related issue with this. However, it is more suitable for use in controlling potential hazards. The working principle of OPC means that it cannot serve as a means for high-speed data communication; therefore, it is not advisable to rely solely on OPC for communication in situations such as those you described, where the process is complex and requires precise control. It is recommended to use OPC for monitoring most of the data – namely those points that are not involved in regulation, interlocking, or program control, as well as process data points where high real-time performance is not required. For important data, it is advisable to use Hilscher’s M6.5.2 DP or Modbus communication modules to establish direct communication with AB’s PLC at the control level. It seems that AB directly supports Modbus communication; DP communication requires a module for conversion, but DP offers a higher transmission speed than Modbus. The choice between the two should be determined through a comprehensive evaluation. These are my humble opinions; please feel free to offer your feedback.
Control is possible; the key point is that once it’s done, the operation will be different from the previous methods. The operation panels of AB and those of Allen-Bradley are definitely not the same. For example, when opening a valve, the ABB panel has options for: Start and Stop. Then in the lower left corner are details such as the point. The operation of AB is* completely different. If it’s just for control, then add two buttons, one for on and one for off. That would be too ugly. But if you want to achieve an AB-style user interface, it seems impossible.
The points for normal communication don’t participate in control, right? For communication between our 652 and Siemens, we use the FM020 communication card, with a master-slave setup; however, it only reads data and does not write any data. If you manage to solve this problem, please share your solution; it might be useful in the future
The communication volume can reach up to 3,000 points; this is a fairly high level of communication, and data refresh delays may be significant.
1. The communication time has increased; it can be measured – it should be 1-2 seconds more； 2. I’ve never seen OPC communication control implemented in this way; it creates additional failure points ；
If the score is low, will the cycle be shortened?
If the score is low, will the cycle be shortened?
How can we see the comments upstairs?
Ask how it was ultimately achieved