Communication between jx300xp and Cooper air compressors
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That person has worked on setting up Modbus communication connections for the jx300xp controller and Cooper air compressors. I can only read the first value correctly; all the others are wrong!
It’s hard to say, because if you can read a value and it is correct (although this value can also change), then there is no problem with the communication (settings, cables, etc.); the issue must lie in your program design, possibly due to an incorrect address for the required data.
Since a value can be read, it at least indicates that there is no issue with hardware communication; check the reasons in the software settings by searching step by step – first look at the JX-300XP, and then examine Cooper’s MODbus communication settings. I’m not sure if the original poster has resolved the issue yet; I hope they have, and that they can share their experience.
In this situation, Zhejiang University Zhongkong and COOPER need to work together to solve it; it’s essential! Now, technical barriers are still everywhere!
I remember that when connecting our factory’s JX300XP to a PLC, we purchased the XP244 card specifically for this purpose; I wasn’t involved in the configuration process. However, judging from Zhejiang University’s control system configuration software, it shouldn’t be very complicated – there’s an online help function, and if that doesn’t work, there are also consultation phone numbers available.
The problem is solved! The issue arose because when using ModScan to perform scans of the master station, I selected the default address length of 100; in reality, there are only 33 register addresses, which caused communication timeouts. By chance, I changed the address to 1, and communication worked properly. Then I gradually increased the address value to 33, and the data matched what was displayed on the on-site human-machine interface. However, when the address value was increased beyond 40, communication failed. It seems that the register addresses are limited; communication will fail if the limit is exceeded. I hope this will be helpful to everyone!
Could you send me Cooper’s MODBUS communication address and tag list? lxw68cn@yahoo.com.cn