05-19-2020 05:47 AM
Hi everyone,
I want to measure both Voltage and Temp from a NI9215(V) and NI9217(°C). I want both working on variable sampling rates, which can be manually edited in the Code, which is working for the Voltage. When reading out only the voltage, i can change the sampling rate, no problem. But when i add the RTD the sampling rate of both is limited to 1Hz.
Long time searching and trying i cant really understand and fix this. Maybe you can help! 🙂
this is the code with which i currently read out the data from the RTD: (https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019ZWxSAM&l=de-DE adapted from here)
task.ai_channels.add_ai_rtd_chan("cDAQ1Mod2/ai0", units=TemperatureUnits.DEG_C, rtd_type=RTDType.PT_3750, resistance_config=ResistanceConfiguration.FOUR_WIRE, current_excit_source=ExcitationSource.INTERNAL, current_excit_val=0.001)
task.timing.cfg_samp_clk_timing(10, source="", active_edge=Edge.RISING, sample_mode=AcquisitionType.FINITE, samps_per_chan=1000)
It works but not at the desired sampling rate.
Hopefully you can understand my problem and know a solution
Best regards, Benedikt
P.S: if necessery i can upload the whole code
I checked in the Automatoin and Measurement Explorer witht the testpanel, where the module is working fine with higher sampling rates...
05-19-2020 08:45 AM
hello,
i installed two more sensors to measure the temperature and it seems this slows down the whole process even more...
i checked the timings of the individual steps and it appears, the most time is used by reading the data with:
data = task.read(number_of_samples_per_channel=1)
i got 3 Modules with:
1.) 20 Slots measuring the Voltage
2.) 8 Slots measuring the Temp
3.) 8 Slots measuring the Temp
By Changing the number_of_samples_per_channel in any direction follows a crash...
Honestly i don't know where the problem seems to be. because the reading of only the Voltage is no problem, but when adding 3 Temps it totally crashes.
Thanks everybody!