Vidmas30 Posted January 3, 2011 Report Share Posted January 3, 2011 Hello, everybody! Happy NEW YEAR! And now about our problem.. We have a net of 3 PLC's and monitoring computer with SCADA. All the PLC's controll various processes in their controll rooms and exchanging data with SCADA computer. All PLC's connected with each other CANbus net and because 1st controll room is near, we used serial connection to connect it to SCADA computer, where OPC server is ran and wonderware SCADA. In attached picture you can see topology we made. All cables are 5e cat. FTP cables (it was not our choise-other company made installation). In PLC's with ID 1 and 3 we put EOL resistors on CANbus connection. On each PLC's power-up we store id numbers to SI8 and initialize CANbus (ISC) with 100kb baud rate. PROBLEM: at first and for some time thereis no problem: data exchanging goes fast and good (data exchange is made every 2sec). But after some time, computer looses PLC of control room 3. Sometimes data exchange is restored (after some time) sometimes not. Sometimes computer looses PLC of control room 1 or 2. At first we thought it is because of cable length and changed the CANbus baud rate to 50kb (to all PLC's). But problem still occurs.. Maybe it's because there are used FTP cables?.. Please, it would be nice if someone could share his oppinion about CANbus network. THANK YOU! Quote Link to comment Share on other sites More sharing options...
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