Need help getting accurate counter measurement using USB-CTR04

[YoelGee]

I am reaching out to seek assistance with an issue related to the MCC USB-CTR04 device and the measurement of voltage frequency.
Currently, I am using the UL example code provided for frequency counter data logging. However, I have noticed that each time I measure the voltage frequency, the device seems to overshoot the actual frequency by a considerable margin. Despite trying various adjustments, such as modifying the Measurement Time and the number of samples to read, the problem persists.
I also attempted to utilize the Python example code for the counter in my program, but unfortunately, it also yields inaccurate results with the frequency overshooting. The DAQami application is the only software I've used so far that correctly measures the frequency without any issues. For your reference, I have attached screenshots of the two measurements for a clearer understanding of the problem.
I sincerely appreciate your time and look forward to any kind of help/ clarification.

PS: the following is when I'm outputting 400KHz at 2V

Edited July 27, 2023 by YoelGee
mention the frequency output im at

[Fausto]

Hello @YoelGee.

Which versions of InstaCal, DAQami, LabVIEW, and Windows are you using?

I tested your scenario with a USB-CTR08, InstaCal v6.74, DAQami v4.2.1, LabVIEW 2023 Q1, and Windows 11, but could not reproduce your frequency discrepancy between applications.  Have you tested a different counter input channel and even used a different PC?  Do you have other applications running in the background?

What is the serial number of your USB-CTR04?  Is it a new device or do you know its history?

Regards,

Fausto

[YoelGee]

I am using windows 11 version 22H2 , DAQami version 4.2.1, and LabView 2020. And yes I have used a different counter as well as a different laptop but the values I am reading on LabVIEW still have the discrepancy.
SERIAL NUM : HE1931668

Edited July 29, 2023 by YoelGee