USB-1616HS-BNC Analog input channel triggering - follow up question

[Montelius]

FOLLOW UP QUESTION - Hello, Jeffery!

Would you have time to provide a short general overview response (and possible references to documents) on how to incorporate the USB-3114 in providing programmed reference voltage levels to the added external array of op-amp comparators in the generation of a trigger signal from any of USB-1616HS-BNC Analog input channels as you have suggested below? I don't understand the interconnects and the flow quite yet.

Best Regards,

Robert Montelius

RE: Jeffrey's response - Thinking outside-the-box, you could set up some number of op-amps, configured as comparators (one for each analog channel you want to use), with each comparator's threshold set to your desired value, wire OR the outputs together, and connect that output to the digital trigger input.  In this way you can satisfy your multi-analog input requirement.

To control the thresholds programmatically, you could utilize a USB-3114 (16 analog outputs  https://www.mccdaq.com/pdfs/manuals/USB-3114.pdf)

Regards,

Jeffrey

[Jeffrey]

Hello Robert,

Here is a general purpose op-amp based comparator schematic for multiple channels:

There are many choices for Op-Amp selection.  LM741, LM747 (dual LM741) are just a couple.  A quick Google search for "General purpose Op amps" will return a good selection.

Here are a couple links to app notes you may find helpful:

https://www.edn.com/using-an-op-amp-as-a-comparator-here-is-what-you-need-to-know/

https://edn.com/wp-content/uploads/AN-849.pdf

User's manual for the USB-3114:  https://www.mccdaq.com/pdfs/manuals/USB-3114.pdf  See page 14 or 23 for pin out.

For information on how to program the USB-3114 using the Universal Library, https://www.mccdaq.com/pdfs/manuals/Mcculw_WebHelp/ULStart.htm

From Hardware Reference, click Analog Output Hardware >> USB-3100 Series.  the library function to output a User defined value is cbAOut()/AOut()/a_out() for Win32, .NET, or Python for windows respectively.

The above information is by no means complete.  Measurement Computing offers suggestions only for additional circuitry.  It is the User's responsibility to verify the design of provided circuitry.

Regards,

Jeffrey