[Python] VI_ERROR_TMO (-1073807339): Timeout expired before operation completed

I try to connect my Power Analyser Rohde&Schwarz, HMC8015 ('ASRL3::INSTR') to my computer, and to read any data that my device can show with python VISA. I have a lot of problems with the code line, which allows to read my device data.

My code is:

import visa

rm = visa.ResourceManager()
name = rm.list_resources()

#using with allows to close explicitly the resource at the end of the script
with rm.open_resource('ASRL3::INSTR') as Power_Analyser:

Power_Analyser.values_format.is_binary = True
Power_Analyser.values_format.datatype = 'B'
Power_Analyser.values_format.is_big_endian = False
Power_Analyser.values_format.container = bytearray

Power_Analyser.timeout = 25000 #2,5 seconds

Power_Analyser.write_termination = '\n'

Data = Power_Analyser.query_ascii_values('P?',datatype='s')[0]
print(Data)

#write the Data to a file on my PC
PCfilePath = 'C:\\Users\\ApCha\\Documents\\Python Scripts\\a.txt'
newFile = open(PCfilePath, "wb")
newFile.write(Data)
newFile.close()


It shows me: VisaIOError: VI_ERROR_TMO (-1073807339): Timeout expired before operation completed.

No matter how big the timeout is set. I'm guessing that the problem comes from the syntax in Power_Analyser.query_ascii_values('P?',datatype='s')[0] but I can't figure out what's the correct syntax.

I checked on my device manual: https://scdn.rohde-schwarz.com/ur/p.../gb_1/h/hmc80115/HMC8015_SCPImanual_en_01.pdf

but nothing seems to work and nothing is clearly explained for python VISA and I don't have any experience with that. Does anyone know how to fix the problem ?

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