So, I needed just 6720 bps to capture the waveform with both instruments. But the software wouldn't let me do everything I wanted, such as continuously and silmultaneously run the analog inputs and digital outputs. So, I wrote a VB application to control the digital and analog functions of both instruments. Figure 3 shows the control panel I designed. The initialize button in the center runs code that sets both instruments to known states.
Separate buttons initiate the analog input and digital output ports of each device.
I don't program often, so I appreciated having some example code. Both IOtech and National Instruments provide programming examples for their USB products. With sample programs, you can copy and paste working code into your application, then modify the code to meet your needs. You send a command and see the results. If you start with inputs, you have to send a command, read the data, and transfer it to the computer.