Siglent SDM3045X multimeter not measuring frequency correctly

[howard123]

Good morning

I have a new Siglent SDM3045X multimeter which is not measuring frequency correctly.
The test frequency being used is a 5 volt p-p 10kHz rectangular signal which has it’s pulse width adjusted to show that at certain pulse widths the SDM3045X meter does not read frequency correctly. On the meter I have tried using the auto as well as the 6v range and the rise time and fall times are 20nS.

Here are the test results:
Applied pulse width - SDM3045X frequency reading
1uS - correct
5uS - correct
10uS - correct
20uS - correct
28uS - no reading
revert to 20uS - no reading
30uS - random reading
31us - correct
52uS - random reading
54uS - no reading
82uS - correct
95uS - unstable
96uS - no reading

I have used other input frequencies with similar results.  I have tried ac coupling as well as dc coupling the meter input, without an improvement.

It is mostly problematic as one can never be sure of a frequency reading without studying the symmetry of the wave. Sine wave measurements are correct.

On contacting the Siglent factory I got this response; “Yes, the measurement for the pulse signal will be not stable. Usually the frequency measurement is more suitable for the sine.”

Has anyone solved this issue?

thanks Howard

The product details are s/n 34FBQ4R0876     SW 5.01.01.07R1  (changed)  HW 03-00-00-05-00

[tautech]

Welcome to the forum.

You could try updating to the latest firmware V5.01.01.07R1 that you can get from here:
https://int.siglent.com/download/firmwares/?ProId=25

[howard123]

Many thanks.
 I have installed the latest firmware but unfortunately that has not helped and the same problem still exists.

[knudch]

Have tried that on my SDM3065X
No problems

Just to be sure that I understand what signal you apply
10kHz/30uS means 30uS ON, 70uS off ?

[howard123]

Thanks for your test result.

Yes 30uS means 30uS high

[knudch]

Just studied the datasheet of 3045X, 3055 and 3065X

They are all different in respect to specification 

I am surprised .... thought that was a simple matter

[howard123]

Thanks
This had actually worked prior to me changing two boards, which Siglent sent me for an unrelated warranty issue.
Seems they have changed the design and spec fairly recently.