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You can see that you send 0x0103 which is read holding registers on device 1. But the device responds with 0x0104, which is read input registers. So there does not seem to be a problem in modbus. Are you sure the address you use contains a holding registers, if not that would explain why. |
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Hello
Since 3 weeks, I try to write a Python program on Rasberry PI to read RS485-RTU data from a new Hypontech inverter.
In his documentation, Hypontech writes a little example of input String to read
Manufacturer Name
but I get a string that doesn't represent a manufacturer name !I contacted Hypontech to obtain output stream that in this case, for address 0x753A is
My Python program using PyModbus version 3.11.3 is following
and output stream obtained is following
At beginning, count value is 16 because it is in Hypontech documentation, but in last email Hypontech proposes to use 8. But result is same !
I also tried address 0x7539 address (= 0x753A - 1) but result is same !
What is strange (form me) is that my resquest is for reading holding registers but logging indicate that
pymodbus
is wait an input register response !!!What is happening ?
What that I do is false ?
PS: in Hypontech answer, response time is more than 11s ! It is very big for a response time ! Perhaps my problem is here.
To allow Rasberry PI to read RS485-RTU serial port, I connected following USB convertissor
https://www.amazon.com.be/-/en/Waveshare-Industrial-Converter-Resettable-Protection/dp/B0B87YJLJQ_B0B87YJLJQ
Best regards
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