EBME Forums Forums Maintenance Test Equipment DNI 454a ESU analyzer help

https://www.ebay.com/itm/3035985129...338722076&customid=&toolid=10050
It's a 125OHM connection, I'm not mistaken, unless the seller is wrong or altered

I mean, 25OHM and 75OHM external resistors have "CURRENT LOOP" connected to the 454a host, but 125OHM does not.0:37 of https://www.youtube.com/watch?v=zYdwkvXRL-0this video,The "CURRENT LOOP" interface should be dedicated to the external resistor, and the current signal of the external resistor may come from here.

The ESU-2350 is really good, but it's too big unless it's been tested in the workshop, which is going to be tough for portable use,And I think BC manufacturers added 'DSP' signal processing, it doesn't matter for actual use.Typically, the actual testing of the ESU is done in one operation room before moving on to the next operation room. Portability is very important.
The power dissipation resistors inside the host take up a lot of volume, it would be revolutionary if only one resistor could meet all the needs。
Looks like an "Electronic Load Tester", I know it's not possible because of the high frequencies, it's just my imagination

That video comes up as "not available".

Meanwhile, for PM etc. (and portable) use, the BC Group ESU-2300 looks good (as mentioned before).

But what's your opinion of the approach (measurement technique)* - no internal loads - used by the ESU-2050? It looks a bit pricey, especially considering all the "accessories" you would need - Pearson current transformer(s), a number of precision resistors, footswitch simulator etc. - plus the CQM-2000 (or similar) for testing REM. But it's lightweight, portable and highly accurate.

* If you believe the reports, it - current transformers etc. - is what the major ESU manufacturers use when calibrating their units. Note (by the way) that the ESU-2300 has a current transformer internal to the unit.

DSP? Or DFA? Apparently, "Digital Fast Acquisition" technology digitizes current transformer output signals using a high-speed analogue to digital converter. DFA technology achieves the high level of accuracy associated with modern ESU's, and effectively replaces the Fluke 8920A Wideband Digital Voltmeter previously used by ESU manufacturers (and some lucky biomeds). By the way, I'm sure I'm not the only one who still wonders why Fluke discontinued - and, as far as I am aware, never replaced - the 8920A.

For “CURRENT LOOP”
The video is Dynamics Circuit's video about calibrating 454a,From the video, "CURRENT LOOP" is specially prepared for external resistors.But (https://www.ebay.com/itm/3035985129...338722076&customid=&toolid=10050) this seller sells 125OHM external load without "CURRENT LOOP" pin.i don't know why.

For ESU-2050
It seems to me that it is just a host, and there is no built-in load resistor.If you want to achieve the same test load resistance value as 454a or QA-ES ii, iii, it will be very bulky.ESU-2050, ESU-2300 they look more like the continuation of 454a, because they all use current transformers

For DSP
Using DSP technology in the ESU analyzer, I think it's more of a gimmick。The use of DSP technology will definitely improve the accuracy of analyzer measurement and the perfection of waveform.For the accuracy, I think it is good to be able to reach 2%-5%, and I think the accuracy of 1% has no practical significance,Because the load resistance is difficult to achieve 1%, even if the temperature change is achieved, the accuracy will be affected,Reliability and portability are more important than accuracy

For Fluke 8920A
8920A is a very good meter,Its 20M bandwidth has not been surpassed so far.(After the discontinuation of production, many ESU manufacturers use RHODE & SCHWARY URE 3 for calibration),Especially for the analysis of Jianfeng waveform, it uses the same heat conversion principle as 454a, I think this is objective and scientific.Maybe the LT1088 discontinuation is the main reason.I also have an 8920a that I've been using and it's been pretty accurate over the years

Most of us can only dream of owning test equipment like the Rohde & Schwarz URE-3 RMS/Peak Voltmeter (up to 30 MHz). But it's already "old" (1990's?), so let's hope they don't discontinue it.

"Jianfeng waveform" ... would that be the work of Jianfeng Weng? I had not come across that notation before.

But here we go. The bit I liked the best comes at the end:- Fourier's Song!

DSP technology is very good.I'm not against using DSP.but look here(https://www.ebme.co.uk/forums/ubbth...000d-7000-are-terrible-testers#Post76806)
Fluke IMPULSE 6000D DEFIB analyzer Used TMS320F2812GHHA,It is a DSP chip.Frequent failures in actual use and difficult to repair
There is also 6000D, which cannot work when the battery is fully charged. You must disconnect the battery and reset it. The battery is installed at the bottom of the motherboard, and it is a Ni-MH battery.
At first, I guessed that my 6000D may have been used for a long time (about 5-7 years),So I bought a 7000, also made by flukebiomedical, but still the same,The new 7000 defibrillation analyzer has only been used for 3 days, and it cannot be turned on when it is fully charged. It is necessary to disassemble the main board, separate the battery from the main board, and it is normal again.
So I think this is an inherent failure of the impulse-6000d-7000 and cannot be repaired。

So sometimes the latest tester from the best known manufacturer isn't the best

But the classic Bio-Tek QED-6, it has been working very stable, only using a 9V battery to work

The old Cardiac Recorders defib tester was even simpler - just a hefty resistor and a neon.

To my mind, a lot of modern test kit (and, indeed, equipment in general) is too "smart" for its own good; often full of unnecessary "features". And (as your example shows) is not necessarily well designed!

Especially during routine PM (on which a lot of in-house biomeds spend a lot - if not most - of their time), all that's needed is a quick and easy "check" that all is well. With a bit of thought (and basic understanding) you can usually come up with a single test (or maybe just one or two) that "prove" the equipment being looked at, without testing every single feature and/or to the "nth degree". If such a test fails, then the kit is removed for more detailed investigation, and a Job Order raised if necessary.

Old guys like me have been lucky enough to "grow up" through the evolution of biomed test kit, and have many favourites from the old days. I always liked Bio-Tek. I always wanted a Lionheart (but had to make do with a little S&W, I think it was). Also Metron - the first to introduce clever stuff like Ansur. But DNI had the best range of test kit (especially when working overseas) - so I must again mention the mighty medTester!

I believe it was a pity that Fluke bought up so many of the smaller (innovative) companies. Of course, BC Group has also consolidated, but - in my opinion - are making a better job of rounding out their range of modern test kit.

I should also mention Datrend, who now have a nice range of biomed test kit. Other names - mainly from the past - include Clinical Dynamics, Dale, Neotech, Timeter, Victoreen et al - and I guess that Pronk is still around. Meanwhile, in the UK, Rigel has always been popular, and (like many others, I suspect) I have fond memories of the 233 Electrical Safety Tester.

Especially if you could justify at least 0.5 hr doing a single safety test (using the 233) of which I had one stolen back in 1989 from the Radiology dept (hidden and under lock and key) here in Rome, most strange as I was the only Biomed........

Well, they were quite an attractive item (also relatively expensive) back in the day. But I always found radiographers to be decent types ... "kindred spirits" (to us), a bit like lab techs. But at least the 70's and 80's were still the era of "wet processing" (that lovely aroma as you entered the department). I'm hoping that, like me, you spent many happy hours immersed (sometimes literally) in the Williamson "Rapid" film processor ("state of the art", at the time).

My then boss wasn't very happy when I got the company to fork out for a 233 as a condition for me returning to Nigeria back in 84/85. He was even more unhappy when most of the kit he had supplied to Lagos, Ibadan, Port Harcourt et al subsequently failed EST. Maybe the humidity was the root of the problem ... but at least it proved that my suspicions had been well founded.

In another life, we bought the "latest gear":- the Bio-Tek 601 Pro (the pre-Fluke, good looking version from the early 1990's). The only trouble there was it rarely got passed booting up due to not finding a decent earth. That was when visiting "desert clinics" and the dreaded (but common) "earth" at the centre tap of the mains transformer situation. From memory, I think the tester needed less than 8 volts between neutral and earth (but often got 110)!

But half an hour per test, Malcolm? Surely not once you got used to it. What did you replace the stolen 233 with, I wonder? Not the 277, I hope.

Meanwhile - and back on topic - have you ever come across the 454A? And (or) any wise words on testing ESU's in geenral?

I was implying "justifying" half an hour not time taken to..... ;-))

and yes the contractor bought the 277 (from the UK in fact which caused all sorts of problems)

Actually the 277 was an interesting piece of kit. Although it must be said that I only got to play with one on a single occasion ... checking it out to see if it was worth shipping (donating) to Africa ... where it is hopefully still being put to good use.

I seem to recall noticing how easy it could be to accidentally switch it off when plugging-in (or un-plugging) the DUT (although that may have been just me being ham-fisted). But you could save results for later downloading to the master PC back at base. Quite advanced stuff at the time.

But did you get to use the "Brain Cell" accessory (scanner, wand ... whatever)? I think it's a pity that didn't catch on (that is, didn't become widely adopted), and that the 277 itself wasn't developed further (to cater for IEC-62353, for example). Hand-held devices (such as the 288) are all very well, but sometimes a more hefty piece of "traditional" test kit may be more appropriate ... not to mention less likely to get "lost"!

The first image illustrates what I was driving at earlier (post #77146) about manufacturers broadening their range with products originating from "others". Otherwise, note that the 277 appears at the left. The second image shows data from a "Brain Cell" (similar to a modern RFID tag) being scanned into the 277. The third image shows the early Bio-Tek 601 Pro that I alluded to in an earlier post (#77132).