UEI DM397 video review by jwrelectro - Page 1
Forum section: electronics / testgear

author: retiredcaps
author_rank: Super Contributor
timestamp: March 21, 2013, 05:13:09 am
content: UEI DM397 video review by jwrelectro (watching and downloading now as I write this). He also did the Amprobe AM-140 review a few months back.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 21, 2013, 07:34:08 am
content: Feature-rich multimeter. Not too fond of the green LCD and what looked like a poor backlight. 20 point datalogging is a bit lame for a $300 meter. Capacitance measurement lag with autoranging is unbelievable on such an expensive machine. 14s for a 150uF cap in this case. (4s on the UT71D, as a comparison)Not impressed with the Fortune DMM front end chip. Nothing wrong per se, but Taiwan's Fortune company is usually associated with low count rock bottom price meters.Unprotected battery wires passing through the PCB, very close to the 11A fuse, could also be a concern.Close-case calibration is a pain, if you don't have access to a precision Fluke calibrator.

author: Lightages
author_rank: Unknown
timestamp: March 21, 2013, 09:16:04 am
content: Yeah, the capacitance speed is pretty bad. The display is a matter of taste but the backlight does look a little shabby. As far as the battery wire, same as the Brymens and as with the Brymens the UEi is actually UL listed so it can be trusted to have passed the CAT rating tests.I have one on the way so I might be a bit biased but I think it lives up to being one of the biggest bang for buck meters if you buy it at the sale price of $235. If it is closer to $300 then it does have more competition. I will be making a side by side with my BM869 if Dave doesn't get to a shootout with these meters first.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 21, 2013, 09:06:32 pm
content: Another strange restriction that caught my eye on this meter, is the narrow frequency range available. The highest range is 5 MHz only. The UT71D, as a reference, has 2 extra ranges, up to 400 MHz.Also, the capacitance readings, like conductance, are limited to a 5000 count display, instead of 50,000.

author: Lightages
author_rank: Unknown
timestamp: March 21, 2013, 09:30:57 pm
content: The Brymen also has a very wimpy 1MHz maximum rating.If we could get the UT71D or E with proper input protection and reliable accuracy, then they would be the best buys out of all the multimeters I have seen. The fact that they lie about their CAT ratings and that my UT71E came way out of spec new out of the box leaves me very unhappy to recommend a Uni-T for anything in their high range.For the UEi DM397 and even with its limitations, it is easy to recommend it as a middle to high range price multimeter. At $235 including PC connection and software, high accuracy, a real CATIII/1000V rating, and with many features it is IMHO a class much higher than anything Uni-T offers and it has a 5 year guarantee!I think this and a UT61E as a partner would make a great dual multimeter setup for less than $300, both with PC connections possible and with the UT61E picking up the frequency range the DM397 can't read. Keep the UT61E for use on low power electronics and co-measurements with the DM397, and use the DM397 for high energy circuits and high accuracy especially where the UT61E falls down on current range voltage burden.Is it a perfect meter? No. I will know better in a few weeks once mine shows up and I can do a direct comparison with my other meters.BTW, I forgot to thank jwrelectro for taking the time to make a good video on the subject, so..... Thanks!

author: Unknown
author_rank: Unknown
timestamp: March 21, 2013, 09:32:54 pm
content: 5 MHz is not particularly low in my opinion. DMM frequency measurements are typically used for things like PWM drives and motor speeds. I wouldn't trust the banana jacks with 400 MHz anyhow, what's capacitive loading going to be like? I wouldn't use them directly on a crystal, for example, the lead capacitance will swamp the load capacitance, affecting the frequency (best case) or preventing it from oscillating.

author: Lightages
author_rank: Unknown
timestamp: March 21, 2013, 11:28:42 pm
content: I wouldn't be looking to measure 400MHz on a multimeter as you said alm, but looking at things up to 40MHz should not be a problem. The Agilents have a pretty high range to 100MHz.

author: jwrelectro
author_rank: Newbie
timestamp: March 22, 2013, 04:13:39 am
content: Quote from: Lightages on March 21, 2013, 09:16:04 amLightages, I think you will be happy with the backlight on the DM397. As I indicated in the video it is not bad in fact I think some will think it looks good. Sorry the video doesn't do the backlight justice. I will be interested in your opinion of the unit when you receive it.John

author: Wytnucls
author_rank: Super Contributor
timestamp: March 22, 2013, 12:58:00 pm
content: The CAT rating compliance for this meter dates from 1995 (IEC 1010-1 and UL3111-1), hence the lack of a CAT IV rating.As you know, the regulations have changed several times since then.For instance, nowadays, 2000V instead of 1000V has to be applied to the amp jacks, with ruptured fuses in place, to check for arcing on the traces.So, although it has the right fuses, that's not the whole story.There is no MOV or spark gap to be seen on the PCB, which is strange, as the manual mentions that the current limiting resistor and the spark gaps would have to be replaced in case of overvoltage.All it has, is a PTC on the Volt side.I checked the UT71D for high frequency measurement with banana plugs. At the limit of my function generator, 20MHz, it is right on the money, reading 20.000. I can't say what would happen with a higher frequency, but the manual mentions an accuracy of 0.01%+8 should be expected up to 40MHz. Anything above that is unspecified, probably for the reasons that Alm talked about earlier.

author: Unknown
author_rank: Unknown
timestamp: March 22, 2013, 06:43:02 pm
content: Quote from: Lightages on March 21, 2013, 11:28:42 pmI wouldn't trust it for 40 MHz signals either. The input impedance of the meter + leads will be in the order of 50 ohms at 40 MHz. Hook up to 1m test leads to a scope once, and feed it a 40 MHz square wave. You'll see all kinds of ringing due to parasitic capacitance and inductance. What's this going to do to your triggering? I would use a frequency counter with a 10x probe for this, even 1x scope probes are useless beyond a few MHz.

author: Lightages
author_rank: Unknown
timestamp: March 22, 2013, 07:14:02 pm
content: Feed the multimeter with a 10X probe and a BNC adapter...... Not perfect but better.

author: Unknown
author_rank: Unknown
timestamp: March 23, 2013, 11:28:51 am
content: That might help, actually. If the meter has a 10 Mohm input impedance in counter mode, then the probe will become a 2x probe with a much higher capacitance. The probe will be way undercompensated anyway, but it should help with the circuit loading and some of the signal integrity issues.

author: Lightages
author_rank: Unknown
timestamp: March 23, 2013, 02:08:59 pm
content: Actually it helps less than I thought at first. Maybe it would be worth coming up with simple circuit to use a scope probe with the right characteristics for use on a multimeter.

author: firewalker
author_rank: Super Contributor
timestamp: March 23, 2013, 02:17:22 pm
content: The bar graph doesn't work when in Hz mode?Alexander.

author: jwrelectro
author_rank: Newbie
timestamp: March 23, 2013, 08:45:18 pm
content: Lightages, I am responding to your request to compare the Amprobe AM-140A to the UEI DM397. Please keep in mind I am biased towards hobbyist. For me their cost was similar. The Amprobe was $162 USD plus $65.00 for data logging and the UEI was $215.00 USD with data logging.The UEI is a little larger and heavier than the Amprobe. I like the display contrast/color better on the Amprobe. Also the tactile feel of the Amprobe is slightly better but the overall construction was good on both meters. The Amprobe autoranging, at least on resistance is faster. They both seems to read test signals about the same. For example a DC voltage on the Amprobe was 4.9999 V and on the UEI it was 4.9992.I really like the dual display feature of the UEI! The UEI backlight is much, much better than the Amprobe although for me I will probably never use the backlight feature on either meter. I cannot compare the software because at this time I haven't been able to install the UEI application (32-bit, 64-bit problem). In terms of the feature set the UEI is way ahead of the Amprobe. The Amprobe is CAT III and IV while the UEI is CAT III.I like both meters but probably for daily use I would grab the Amprobe. Hope this is helpful.John

author: Lightages
author_rank: Unknown
timestamp: March 24, 2013, 03:16:27 am
content: Thanks for your thoughts o these two. Sounds like it comes down to specific use and personal preference.