Math error?

[RTSLVU]

Apparently 4,000,000 = 5,000,000

[mcduff · Accepted solution]

The problem is your sample rate is not what you think it is. You are setting it for 20MHz, but NI-Scope coerces it to 25MHz. Use the function below to see the real sample rate. (Put it after your Set Horizontal function and ignore the error from the Horizontal).

So you need to find out your allowed sample rates, hint 20MSa/s is not one of them.

mcduff

[RTSLVU]

Oh... Thanks I was just about to get to that and was pulled into a meeting.

Anyway I think it will just change my control to say 25Mhz if 20 is going to be coerced to 25 anyway.

[mcduff]

Look at this link

"The horizontal timing parameters are all inter-related to comply with the IVI-Scope specification"

Not sure if 20MSa/s is allowed is some situations but not others, you might want to look into this.

This is a guess here, I don't have an 8-ball to shake, but I think allowed sampling rates need to be an integer factor of the max-sampling rate, ie 50MSa/s divided by 20MSa/s is 2.5, so 10MSa/s is good, 25MSa/s is good, etc.

I suggest using something like the following in the beginning of your program to get a range of sampling rates, I would make it dynamic so if you change scope models, you don't need to do anything.

mcduff