I am aware that most UNI-T frequency counters on multimeters are limited to 30V of input voltage.
I don't have any Uni-T's multimeters, but I'm totally surprised at this limitation. I have NO background or formal training in electronics/electricity at all.
About 6 months ago, I considered getting a UT61E due to the positive reviews, but I managed to find some used Flukes for some very reasonable prices. Since they are used, I test every function to ensure they work and I use mains to test out the HZ function.
I even had a $50 Amprobe AM-60 with HZ capabilities and plugged the AM-60 into mains without problems.
The assumption that every multimeter or dedicated frequency counter should be capable to measure frequency of Mains it is a wild one.
But no one can blame an IT specialist because he made such a wild assumption.
Retiredcaps@
The violation of written specifications’ usually called as misuse and voids the Warranty.
I can not blame the company if they did not respond.
I agree that the limitation is documented and that this is user error. However, this is a good opportunity for Uni-T to make their multimeters more robust. I'm not a multimeter design engineer, but perhaps they can make the HZ fail in a way that doesn't completely brick the multimeter.
I mean we all make mistakes when we are distracted, tired, and/or forgetful so multimeters manufacturers should take this into consideration and try to protect the user and the equipment.
Let's say that Martin did notice the HZ voltage limitation and didn't kill the UT90C, but 3 weeks later he lends this multimeter to a friend and he decides to test HZ on mains. Does Martin need to put a warning label above the HZ symbol?