As a newcomer to the Twincat and Beckhoff system, I am utilizing the CX7080 along with some IO terminals. The CX7080 is connected to a PC via an RS485 bus for communication in half-duplex mode. It is expected to respond to queries received from the PC GUI. While everything is functioning properly, occasional incorrect frames are transmitted by the CX7080. The baud rate is set at 9600, and bus termination is implemented on both ends of the cable, which has a length of approximately 10 feet. The screenshot of the settings is provided, along with the serial communication code. The typical query and response sequences are exemplified below: Query: *01T!@01T03902502502502502502502559# Response: *01H!@01H0000000042# In the event of an issue, the response may appear as follows: @01T0780260?M??????????? @01T078026026?????????? @01H0000000042# The code snippet for the serial communication entails various variables and settings for proper functionality. Additionally, the configuration for half-duplex communication is scrutinized to ensure smooth operation.
Looking for guidance on RS485 half duplex communication with CX7080 and Twincat? I am seeking information on how the internal RS485 driver direction is managed in half duplex mode for the CX7080 in Twincat. Can anyone offer insights or advice on this topic?
From your description, it sounds like your configuration is mostly right, but it seems like some disturbance might be causing those incorrect frame transmissions. There's a possibility it could be noise interference. Given the length and the type of your cable, make sure it's not running parallel to any high voltage lines, which could cause potential interference. Additionally, it might be worth checking the quality of the cable itself, because sometimes even slight defects can cause issues in transmitting correct data. Finally, ensure that there's no internal software glitch causing this issue. Perhaps, trying to update software or firmware could address the problem. Your code might also benefit from including some form of error checking or retry mechanism, if it's not already present.
It seems like you've done a good job setting up and troubleshooting so far, though the irregular incorrect frames can indeed pose a problem. The issue could be stemming from electrical noise on your RS485 bus, considering your setup seems optimal. I would suggest trying shielded cabling if you haven't already, it can really help mitigate interference. If the problem remains, you may want to look into adjustable resistors for better line impedances matching at both ends of the connection. Also, addressing your programming, a good practice might be to add a cyclic redundancy check (CRC) to detect and correct any errors in your communication frames.
Hmm, from your query-response sequences and the problems you've encountered, it seems there might be some kind of noise or interference in the line causing these erroneous frames. Ensuring your cabling is of good quality and properly shielded can help reduce this issue. However, long cable runs are often more susceptible to outside electrical interference, so it may be worth exploring that, even though 10 feet isn't exactly long. Additionally, don't forget to check your baud rate and half-duplex settings - these could cause frame errors if not correctly set. Lastly, there might be bugs in your code leading to these erroneous transmissions, so giving your code another look or having a fresh pair of eyes inspect it can never hurt.
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Answer: - Occasional incorrect frames could be due to issues such as electrical noise, improper termination, baud rate mismatch, or code errors. It is essential to investigate these factors to pinpoint the exact cause of the problem.
Answer: - The recommended settings include ensuring proper termination at both ends of the cable, setting the correct baud rate (in this case, 9600), and carefully reviewing the configuration for half-duplex communication to avoid errors.
Answer: - Troubleshooting steps may involve checking for noise interference, verifying termination, confirming baud rate consistency, reviewing code for errors, and monitoring the data exchange for any anomalies. It is crucial to systematically analyze each aspect to identify and resolve the communication issues.
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