USB-1208HS-4AO

[Bartłomiej Sikora]

Good Morning,

     I have bought USB-1208HS-4AO and would like to control/plot/aquire data from 4 AI channels and 2 AO channels with the given sampling frequency up to 5kHz as close to synchronous mode, as it is possible. I am using the Python UL, but I am a quite new Python learner, so any tips/tutorials or code advice will be a great help for me. I am trying with a_in_scan and a_out_scan.py + pulse_out.py as a trigger, but it seems, that these operations are not running at the same time. Should I change the OS or programming language? Maybe LabView? I am open for any suggestions!

Best Regards

Bartłomiej Sikora

[JRys]

Hello,

Often overlooked is our UL Help that can provide useful information about a specific product. The shortcut to it can be found on the Measurement Computing start program menu. A good place to start is to click the Search tab and perform a search on "USB-1208HS-4AO". This will provide a link to the device's page, which lists the functions and scan options to use. There you will see that both the AInScan and AOutScan functions support the external trigger option - EXTTRIGGER.  If you include this option in the scan options for both functions, neither process will start until a rising edge of a +5 volt pulse is detected on pin 39 - see page 0 in the user manual for pinout names. 

There is another better way, instead of EXTTRIGGER use EXTCLOCK. With this option, neither will run (and continue to run) until a +5 volt square wave clock is applied to pins 35 & 37. For a clock signal, use the timer output and connect pin 43 to 35 & 37. This assures both run in lock-step until the clock is removed.

regards,
John

[Bartłomiej Sikora]

Dear John,

     Thank you very much for the valuable advice, according to which I was able to get the first measurements, but I still have some confusion about the code (pmDataScan1208HS.py), that is how to acquire synchronously AI and AO data. I attached a program that utilizes pulse_out, ai_scan and ao_scan in EXTCLC mode. The code is basically copy-paste three functions You have mentioned with minor changes. There are lines 81,82, where in the pulse _out function I call ai_scan, ao_scan. How could I be sure of the measured data synchronization? I will be very grateful for further advice, where should I start to work with this code. Also my experience up to now was around control systems in Simulink, but in a new job I may use Python or LabVIEW. Would You recommend me to start building control system in LabVIEW rather than with UL Python Library help? First task will be a real-time  temperature control in peltier module. Next project may include high-speed rotating machinery diagnosis. Any advice, how to speed up rapid prototyping with such applications will be very useful.

Best regards,

Bartek 

pmDataScan1208HS.py ul.py