UT61E Frequency Counter - Page 1
Forum section: electronics / testgear

author: picitup
author_rank: Regular Contributor
timestamp: September 30, 2015, 05:50:12 pm
content: I've noticed there aren't many UT61E threads on the forum so I thought I'd add another one :-) I couldn't find any threads on the frequency counter so here goes......Armed with my new 0.2Hz -20MHz function generator, I decided to try out the UT61E frequency counter. According to the manual the specs are as follows:10Hz - 10MHz input voltage must be between 300mV and 30v RMS10MHz - 40MHz input between 400mV and 30v RMS> 40MHZ - unspecified.Meter is advertised as having a frequency counter from 10Hz to 220MHz.Well the above specs don't look too bad at all, but when I tested the meter I got nowhere near. Below are the peak-peak voltages I checked and the actually frequency range of the meter. When you go outside the frequency range of the meter, it simply zeroes the display:1v 2.73Hz - 290KHz3.3v 2.3Hz - 715.1KHz5v 2.93Hz - 1.28MHz10v 2.25Hz - 2.06MHz15v 2.4Hz - 1.438MHzSo my measurements are miles away. Has anyone else tried to test the freq counter in a UT61E? Has anyone else got any better results?Thanks for reading....Steve

author: Wytnucls
author_rank: Super Contributor
timestamp: September 30, 2015, 06:09:52 pm
content: 1Vpp 2.10Hz~20MHz with good accuracy. (Rigol DG1022)

author: picitup
author_rank: Regular Contributor
timestamp: September 30, 2015, 06:20:18 pm
content: Well I'd be happy with that! Did you use any particular setup or did you just connect the output of your Rigol to the meter?I wonder if mine is faulty?

author: ocw
author_rank: Regular Contributor
timestamp: September 30, 2015, 06:24:52 pm
content: While requiring an input level of +23.5 dBm/224 mW/3.346 V for its upper frequency limit, my UT61E was able to measure up to 225 MHz with reasonable frequency accuracy. That was via a dual banana to BNC adapter at the UT61E input.

author: picitup
author_rank: Regular Contributor
timestamp: September 30, 2015, 06:35:45 pm
content: I just used the meter leads. I think I have a banana to BNC adaptor so I'll give that a try tomorrow. Thanks for the tip.Steve

author: Wytnucls
author_rank: Super Contributor
timestamp: September 30, 2015, 07:47:26 pm
content: Same here, banana to BNC.

author: picitup
author_rank: Regular Contributor
timestamp: October 01, 2015, 05:37:46 pm
content: Well I have to admit to being a bit stupid. I hadn't used the meter for a while and I did do a quick search in the manual and I've mistakenly been using the Hz setting on the Volts position rather than the dedicated HZ/% position. Obviously I'd not drunk enough coffee.After reading the manual, the HZ on the Volts position only goes up to 1KHz so I've actually been getting much better readings. Funnily enough, using the Hz% position works great up to just over 20MHz which is the upper limit of my TG120 function generator.I don't mind if you laugh, 'cos I know you'll be laughing with me, not at meThanks to all that replied.Steve

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: October 01, 2015, 06:12:33 pm
content: Ive tested a 28.8mhz CML output TCXO on bothe the 61E and 71E. The meter read it just fine, although I did pull the signal up to a 5v rail, since CML output is sooooo low, the meter wouldn't read the frequency at such low voltages, but with a pull up it was dead on at 28.8 on both meters. So the lesson here is if you need to use a UNI-T as a freq counter (which I do all the time, since the 71E goes up to 400mhz) just try to test out of circuit if you can and pull up the voltage to the appropriate level in the manual or higher

author: picitup
author_rank: Regular Contributor
timestamp: October 01, 2015, 07:34:43 pm
content: That's a good tip, thanks I'll keep that in mind. I just took a look at the UT71E and it has some nice features; 40000 count, high frequency counter, on board storage for data logging and memories to manually store readings.Well, Christmas is not too far away.....Keep Smilin'Steve

author: Wytnucls
author_rank: Super Contributor
timestamp: October 01, 2015, 08:24:23 pm
content: On the 61E, if you press the meter against your ear, you will hear the signal for audio frequencies, if the voltage is above 15V.

author: Rick Law
author_rank: Super Contributor
timestamp: October 02, 2015, 03:03:49 am
content: Quote from: rwgast_lowlevellogicdesin on October 01, 2015, 06:12:33 pmFrom the user manual:10Hz - 10MHz 300mV <= amplitude <= 30Vrms10Mhz - 40MHz 400mV <= amplitude <= 30Vrms>40MHz unspecifiedWhen on line frequency or duty cycle under AC Voltage and Current Measurement mode:amplitude >=30% of rangefrequency <= 1KHzEDIT (adding these):By the way, I cut and pasted the info on accuracy/limits from different pages in the manual into aone-page spec sheetthat I have on the wall. You can grab that one-page spec sheet here:https://www.eevblog.com/forum/testgear/uni-t-ut61e-multimeter-teardown-photos/526/You have to manually page down to reply 526. Reply 526 is not the first on that web page.

author: Wytnucls
author_rank: Super Contributor
timestamp: October 02, 2015, 04:45:05 am
content: If you measure frequency on the AC volt or amps selector positions, the meter doesn't tolerate any DC offset, whereas on the Hz position, a DC offset is possible.

author: picitup
author_rank: Regular Contributor
timestamp: October 02, 2015, 06:31:48 am
content: Hi Wytnucls thanks for the tips. I did read that the meter will pass audio frequencies through when the input voltage is >15v but my func gen has a max output of 20vpp so just a little over 14v RMS so I couldn't test it.Rick thanks for the single page spec sheet. I too hate trawling through the manual to remind myself of some parameter or other. I've printed it out and put it up on my wall.CheersSteve

author: Wytnucls
author_rank: Super Contributor
timestamp: October 02, 2015, 07:07:26 am
content: 20Vpp is fine. You will hear it. The 71 series has that undocumented feature too.Not sure what it could be used for, but it's cool anyway.

author: picitup
author_rank: Regular Contributor
timestamp: October 03, 2015, 06:08:38 am
content: You're right. I couldn't hear it due to the fan on my scope. It's very quiet though. I can just imagine myself holding my multimeter up to my ear on site lol. I'd probably get carried away!Keep Smilin'Steve