Difference between BM257 and BM257s - Page 1
Forum section: electronics / testgear

author: Deckert
author_rank: Regular Contributor
timestamp: March 31, 2015, 11:10:44 pm
content: Hi,Does anybody know what the difference is between the BM257 and BM257smodels? Almost everywhere I just read "the new improved" model, but nowhere can I really find what was improved. I note that there is now also a BM869s, which apparently is improved over the BM869.I can get the BM257 locally, but if the 's' model is a lot better I'd rather get it directly from Franky.--deckert

author: Lightages
author_rank: Unknown
timestamp: March 31, 2015, 11:21:57 pm
content: The "s" model is the most recent version with some small updates, better fuses, and third party tests to meet the latest IEC CAT rating requirements. It does nothing else different. Get which makes you comfortable.

author: Deckert
author_rank: Regular Contributor
timestamp: April 01, 2015, 09:00:57 pm
content: Hi!Thank you for the concise answer, Lightages!--deckert

author: mimmus78
author_rank: Unknown
timestamp: April 02, 2015, 10:50:42 am
content: I posted some photos side to side few months ago. They made a lot of changes in the input protection board ... but apart from safety no changes in specs. Search in the sticky thread about meter safety ...

author: dadler
author_rank: Unknown
timestamp: April 02, 2015, 06:17:29 pm
content: Sort of related:TME carries the BM257s and I ordered one on Monday for $95 USD (arrives today). I checked the site yesterday and the price is up to $115. $20 jump in 2 days?

author: JonathonD
author_rank: Newbie
timestamp: April 02, 2015, 09:15:12 pm
content: Yes it looks like Tme have raised the price on all the Brymen meters by $20 not overly happy but on the other hand they are still the cheapest I have seen by a mile

author: timofonic
author_rank: Frequent Contributor
timestamp: April 02, 2015, 09:59:41 pm
content: Are Brymen enough good without being a Fluke? Can I live with a bad one and save for a bench top FNMA?

author: dadler
author_rank: Unknown
timestamp: April 02, 2015, 10:11:13 pm
content: Quote from: Circuiteromalaguito on April 02, 2015, 09:59:41 pmBrymens are spectacular meters for the money. Watch this video:I have the BM869s, BM27s, and (if DHL guy would hurry up, moments away!) a BM257. I use the first two more often than my Fluke 287 out of convenience. The fluke wins for offline datalogging, but if you can handle keeping a PC attached, the Brymen datalogging software is nice. And it's free! On the disc that comes with the IR/serial adapters, Brymen includes drivers and full documentation of their protocols, so you can easily write your own software to collect data from the meters if you wish.Build quality is great, but not up to the level of Fluke. The internals are close, most of the build quality differences are in the exterior fit-and-finish. Honestly, the biggest complaint I have about the BM869 vs the Fluke is the center selection dial is hard to turn comparatively. You'd be hard pressed to find a better meter for the money.

author: Lightages
author_rank: Unknown
timestamp: April 03, 2015, 05:29:55 am
content: Quote from: dadler on April 02, 2015, 10:11:13 pmHmmm, I am not sure. I guess it depends on your point of view. The 287 has 10,000 internal records capability. The Brymen BM525 has 87,000 records. So it depends.

author: dadler
author_rank: Unknown
timestamp: April 03, 2015, 09:57:15 pm
content: Quote from: Lightages on April 03, 2015, 05:29:55 amThe BM520 series are 6000 count meters if I am not mistaken. Do they have better resolution over the serial interface/internal logging?I think the 289 has more internal memory than the 287, but I got the 287 because the differences didn't seem to warrant the price premium.Anyways the Brymens are great meters. My BM257s showed up and it is a great little meter. Love the form factor and all of the features in such a small unit. Might be my new favorite (my newest meter usually is!)

author: Lightages
author_rank: Unknown
timestamp: April 03, 2015, 11:38:21 pm
content: BM52X/82X series are 10000 count on Volts and Herz, 6000 count on mV, uA Ohms and Cap., and 0.12% accuracy on 60mV range, 0.06% 600mV, and 0.08% above that. I didn't say it was better than a 287/289, just another one to consider.

author: ru_tash
author_rank: Regular Contributor
timestamp: July 07, 2015, 05:55:12 am
content: Quote from: mimmus78 on April 02, 2015, 10:50:42 amI own BM252s the truncated version of 257s, one thing I dislike is that non-zero offset when leads shortcut on manual range for Ohm meter mode, for instance on the range 60.00kOhm it shows 00.02 kOhm, this 00.02 constantly added to any figures like 02.00kOhm -> 02.02kOhm.Does anybody met same issue on models without "s" or with "s",I did not find any similar notice/observations posted before.

author: retiredcaps
author_rank: Super Contributor
timestamp: July 07, 2015, 06:09:48 am
content: Quote from: ru_tash on July 07, 2015, 05:55:12 amUse the REL key. See manual.

author: ru_tash
author_rank: Regular Contributor
timestamp: July 07, 2015, 06:36:24 am
content: thank you for the answer, I know this workaround, but does this behavior native to all BM25*(s) or this is sort of lottery of having "best/moderate" piece, maybe this is trade-off they made in order to improve "safety" features in "s" models?

author: Fungus
author_rank: Super Contributor
timestamp: July 07, 2015, 07:55:20 am
content: Quote from: ru_tash on July 07, 2015, 06:36:24 amIt affects all meters, all brands, even Flukes. The reason is that the probes always have some resistance. Maybe you could try cleaning yours, see if it makes a difference.PS: The Rel button isn't a "workaround", it's what it's there for!

author: Warhawk
author_rank: Frequent Contributor
timestamp: July 07, 2015, 08:06:14 am
content: Quote from: dadler on April 02, 2015, 06:17:29 pmJust info:I bought BM257 from tme approximately ten months ago and the leads were not with the banana plug adapter at the tip as you may get from franky (I also have extra Brymen leads from him).

author: ru_tash
author_rank: Regular Contributor
timestamp: July 07, 2015, 09:23:57 am
content: Quote from: Fungus on July 07, 2015, 07:55:20 amif you may noticed I indicated example with non-zero on 60.00kOhm range meaning least significant digits 00.02kOhm goes to 20 Ohm of leads' resistance? Impossible! Leads are clean and gold plated. I have $10 DMM (9205A) which does not show such things at all.

author: Fungus
author_rank: Super Contributor
timestamp: July 07, 2015, 10:01:45 am
content: Quote from: ru_tash on July 07, 2015, 09:23:57 amOK, that's not lead resistance on higher scales, it's measurement error.Annoying, sure, but it doesn't really affect anything. 20 Ohms in 60000 is only 0.03% error, it's a useful measurement (and within spec).

author: EEVblog
author_rank: Unknown
timestamp: July 07, 2015, 10:44:28 am
content: Quote from: mimmus78 on April 02, 2015, 10:50:42 amI thought the old 257 was pretty good in the protection department and was UL certified? Why did they need to upgrade?

author: ru_tash
author_rank: Regular Contributor
timestamp: July 07, 2015, 11:58:26 am
content: Quote from: Fungus on July 07, 2015, 10:01:45 amI agree with small correction, if on the scale 60000 measured value 1000 Ohm then 20 Ohm gives 2% error, anyway it would be nice to know how to set this offset to zero permanently (if possible), no trimmers on the board.

author: Lightages
author_rank: Unknown
timestamp: July 07, 2015, 11:08:13 pm
content: Quote from: EEVblog on July 07, 2015, 10:44:28 amThe direct answer I got from Brymen is that the redesigned and retested all of their products to meet the latest IEC standards. This could be construed that Brymen was only doing the minimum necessary before and needed to catch up, or that they are continuously working on improving their products.

author: SkyMaster
author_rank: Frequent Contributor
timestamp: July 08, 2015, 12:06:33 am
content: Quote from: ru_tash on July 07, 2015, 05:55:12 amI have a week old BM257s, with the probe tips touching (or using a short patch cable with banana plugs) the reading is 000.0 ohm and 00.00 Mohm, but the other ranges are all showing a least significant digit that is slowing changing between 1, 2 or 3.I also have a BM319, which is an automotive DMM that has the same form factor as the BM257 (could be totally different internally); the BM319 is showing 0.0 on all of the Ohm ranges.Any in case, the BM257s spec says that the Ohm accuracy is +4 digit on all ranges.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: July 08, 2015, 12:07:57 am
content: Quote from: EEVblog on July 07, 2015, 10:44:28 amThe old spec allowed you to state voltage ratings on each input. So voltage could have one max rating, diode another, resistance another, etc. The new one requires the CAT voltage rating to be uniform across all of the inputs. My bet is it had something to do with that.

author: EEVblog
author_rank: Unknown
timestamp: July 08, 2015, 12:28:53 am
content: Quote from: PedroDaGr8 on July 08, 2015, 12:07:57 amAh, interesting. I'm not keeping up to date with the standards.

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: July 08, 2015, 04:29:37 am
content: Quote from: EEVblog on July 07, 2015, 10:44:28 amAFAIK they also increased the maximum current on the Amps range? 257 was 8A, 257s is 10A.Nicest change for me was probably the sexy silicone probes as standard.

author: Lightages
author_rank: Unknown
timestamp: July 08, 2015, 05:15:13 am
content: To clear some things up:Brymen did not rate their BM257 and BM257s differently for safety on different ranges that I know of.The test leads you receive is the option of the distributor/reseller.It is not the decision of Brymen. There is a price difference.Yes, the BM257s is 10A current, the older model without the "s" is 8A.There is revision on the input protection circuit board in the latest revision. I will, at some time, do a full video on this.There has also been an extra piece of shield plastic added to the battery compartment.