Hello friends, we are using a Siemens S7-300 as our main CPU with various makes and models of drivers and modules such as ET-200 and IM-151. Recently, a Baumuller brand driver briefly caused BF and SF errors in the CPU due to a malfunction. Upon investigation, we discovered that the issue stemmed from a malfunction in the profibus cable connecting the ET-200 modules at two separate points. This setback caused us some time and inconvenience. I am seeking advice on how to handle cable faults in such situations and how to effectively detect them. Given the long distance between the cables, rewiring can be a challenge. Is there a way to identify and address these cable faults using the plc system or any other methods? Your input would be greatly appreciated.
Detecting the loss and return of DP slaves can be achieved using OB86, but pinpointing the exact reason for a DP slave disappearing from the master can be challenging, especially when cabling issues are involved. Fortunately, there are Profibus analyzers available, such as Profitrace, that can offer in-depth error information, specifically identifying cable or connector issues.
For added functionality, the Siemens FB126 block and example project are viable alternatives to using OB86 in PLC programming. Learn more about this topic on the PLCTalk forum: https://www.plctalk.net/qanda/showthread.php?t=101535.
Hello, it appears that the link provided is for Profinet (FB126). Can you guide me on utilizing OB86 in Simatic Manager? Additionally, is there a detailed example or guide on its exact usage available?
Avatar_41 inquired about using OB86 with Simatic Manager. Can you provide guidance on how to use OB86 effectively, along with any examples or explanations? The link provided seems to be for Profinet (FB126), but it should also work for Profibus. Let me know if there are any specific instructions for implementing OB86 with Simatic Manager.
What is the total cable length between nodes and what is the baud rate set for the master? What is the overall execution cycle for an IO payload? It is important to ensure proper termination and investigate any potential cabling issues. If the cabling is functioning properly but a high baud rate is being used, it may be beneficial to lower the transmission speed without impacting the process. Alternatively, incorporating a repeater in the bus can enhance signal quality.
It sounds like you've had quite a hassle with that cable fault! One approach that might help is to implement a cable diagnostics tool or device designed for Profibus networks; these can help pinpoint the exact location of the fault without requiring a complete rewiring. Additionally, using termination resistors at each end of the Profibus segment can reduce signal reflections and improve signal integrity, potentially preventing future issues. You can also consider deploying a network analyzer to monitor the network traffic for anomalies, which could give you a heads-up before a fault escalates. Regular maintenance and testing of the cables would be beneficial too, especially for long runs where wear and tear can cause intermittent issues. Good luck!
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Answer: - Answer: Cable faults in a Profibus system can be detected using diagnostic tools like the Profibus DP protocol analyzer or by monitoring error codes in the PLC system.
Answer: - Answer: Common causes of cable faults include physical damage, interference, improper termination, moisture ingress, and aging of cables.
Answer: - Answer: Troubleshooting cable faults can involve isolating the faulty segment, checking connections, replacing connectors, using cable testers, or implementing signal repeaters.
Answer: - Answer: Regular maintenance, proper cable routing, ensuring correct cable type and shielding, monitoring signal strength, and implementing surge protection can help prevent Profibus cable faults.
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