UT70A - Frequency Measurement shows .000 kHz

[Didix]

Hi there

I got a couple DMMs plus an UTG9002C frequency generator (FG).

When I measure the signal (1V, 2kHz or 20kHz) from my FG,
the UT70A shows .000 kHz, wheras my other DMMs show the right frequency.

Other measurement ranges (V, A, Ohm) on the UT70A work fine.

Any ideas appreciated!

[electr_peter]

What mode of DMM do you use for frequency?
I do not know about UT70A, but typical DMM has 3 types/modes of frequency measurement:

• V DC -> Hz - this mode picks up even low signals and signals with high frequency
• V AC -> Hz - this mode is limited in frequency measurement due to very limited DMM AC BW and possible AC coupling
• separate Hz mode - it is typically similar to DC, depends on DMM

There is some limitation on lowest detectable signal level on all modes as well. See DMM manual for this.

Check DMM mode and connection. Is DMM in a good condition (good AC/DC accuracy, battery is full)?

[PA0PBZ]

Just browsing the manual, it has a seperate Freq setting, 2Khz - 10Mhz, sensivity Less/Equal 0.8V, but they don't say if it is PP or RMS.
So if you have it on the 10Mhz setting and is does not show anything even with 2V you might have a problem...

[Didix]

right, only one dedicated position.

My other DMMs show frequency above around 0.7..0.8V.
The other modes work well (V, A, Ohm).
I will check the battery.

EDIT: My Fluke 76 says
9.37V if UT70A is off
9.04V if UT70A is on

[PA0PBZ]

Did you try more than 1V input?

[Didix]

Problem solved!

It's the sensitivity.

I had my 20dB Button in. So I could not go higher than 2.4V.
With Sinus nothing happens.
Changing to Square helps. Now it triggers above about 1.0V.

Taking out the 20dB Button and going back to Sinus I pushed it now up.
It triggers above 5V.

Well, I did not expect that it needs that much Voltage 
The user manual says: Sensitivity better than 0.8 Vrms

Thanx guys for helping that fast !!