Missing the first 2 bytes after WRITE_SINGLE_REGISTER

[theangusschmaloer]

Hey,
I am implementing ModbusRTU op my stm32 and i am using the rtumaster_example.py.

https://github.com/ljean/modbus-tk/blob/master/examples/rtumaster_example.py.

I have tested my Modbus Slave with the different function.
It all works fine, except when i use:

logger.info(master.execute(1, cst.WRITE_SINGLE_REGISTER, 50, output_value=54)).

Every commando after that one had a CRC error, my calculated CRC did not correspond with the received bytes.
I tried switching the functions around, but it still didn't work.

i looked at the whole string my uart received and there i saw that the string misses the first two bytes, the slave address and the function number.

Greetings,
Angus Schmaloer