What's missing from the market? - Page 1
Forum section: electronics / testgear

author: metrologist
author_rank: Super Contributor
timestamp: July 20, 2016, 08:06:16 pm
content: If you could ask the big mfgs and knew they were listening, what would you want from them? This would be both for B2B and B2C.

author: tautech
author_rank: Super Contributor
timestamp: July 20, 2016, 09:23:51 pm
content: Reasonably priced oscilloscope Current probes.AnordinaryDSO with fully Isolated channels, 2 channels versions for hobbyists, 4 ch for those doing 3 phase work in industry. 100 MHz max versions sufficient.Can it really be that hard?Any takers ? ^^

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 20, 2016, 10:32:35 pm
content: Fully agree about that DSO with isolated channels!

author: Dwaine
author_rank: Frequent Contributor
timestamp: July 21, 2016, 12:42:47 am
content: I vote for "Reasonably priced oscilloscope Current probes" Also differential probes for high voltage. I look at the prices and just say I will not own them.

author: dr.diesel
author_rank: Super Contributor
timestamp: July 21, 2016, 12:46:49 am
content: Companion software that doesn't suck.

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2016, 12:51:33 am
content: Quote from: Dwaine on July 21, 2016, 12:42:47 amAh ha, but with a Isolated channel DSO there's no need for differential probe for other than HV.The need for current probes are reduced too as simple current shunt measurements and be made without worry of Gnd loops.

author: Dwaine
author_rank: Frequent Contributor
timestamp: July 21, 2016, 01:44:17 am
content: Quote from: tautech on July 21, 2016, 12:51:33 amTrue.... I'm still in high voltage land. Mostly tube transceivers, audio amps and power supply 800+ volts DC.

author: Dwaine
author_rank: Frequent Contributor
timestamp: July 21, 2016, 01:47:59 am
content: Adding another to the list.... Active firmware development from hardware vendors. There needs to be a real firmware development team behind the release of new hardware. Not buying some firmware package/something from some company or person. Then finding yourself in a position that you have no clue how to continue the development of the firmware after product release.It's pretty bad situation in this market.

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2016, 01:54:03 am
content: Quote from: Dwaine on July 21, 2016, 01:44:17 amStill no problem for a 100:1 probe, again no differential probe required with an isolated input DSO.

author: David Hess
author_rank: Super Contributor
timestamp: July 21, 2016, 03:10:15 am
content: Quote from: tautech on July 21, 2016, 12:51:33 amIsolated inputs are suitable for single ended signals which have a low common mode impedance to ground. That covers almost all off-line applications but not differential probe applications. The same limitation applies to using a line isolation transformer.

author: David Hess
author_rank: Super Contributor
timestamp: July 21, 2016, 03:13:40 am
content: I want a general purpose DSO with auxiliary sampling front end for high bandwidth and good overload recovery. This is a minor addition to what a simple modern DSO already has to support.

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2016, 04:19:29 am
content: Quote from: David Hess on July 21, 2016, 03:10:15 amYou imply isolated inputs are not differential inputs.Considering a 1M scope impedance input and the further impedance (10M, 100M, 1000M) with the correct isolated scope probe (well insulated reference lead and clip), where's the problem?Educate me please.

author: David Hess
author_rank: Super Contributor
timestamp: July 21, 2016, 05:11:01 am
content: Quote from: tautech on July 21, 2016, 04:19:29 amThey are not differential inputs.Differential inputs have the same impedance to ground or common on each input. Isolated inputs within the context of common oscilloscopes with this feature are single ended inputs with high input impedance on the signal and lower impedance on the ground connection chiefly from capacitive coupling to chassis ground; they are just galvanically isolated.Compare using a single x10 passive probe which has a 10 megohm input resistance shunted by about 12 picofarads and its ground clip versus using two x10 passive probes differentially.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 21, 2016, 05:19:29 am
content: Quote from: dr.diesel on July 21, 2016, 12:46:49 am+1

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: July 21, 2016, 11:35:27 am
content: Quote from: pascal_sweden on July 20, 2016, 10:32:35 pmHow about the Hantek DSO1102S, for about £400https://world.taobao.com/item/535747718360.htm

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: July 21, 2016, 12:02:09 pm
content: Hantek also make current probes for about £40https://item.taobao.com/item.htm?spm=a230r.1.14.15.tpOhow&id=40487955317&ns=1&abbucket=19#detail

author: A.Huggy
author_rank: Contributor
timestamp: July 21, 2016, 12:29:30 pm
content: CAN decoding support. The Rigol DS1054z can already do SPI, I2C, and RS232, why can't it do CAN?This is a capability I need, but I can't find it on a 4 channel scope under $2000.

author: JPortici
author_rank: Super Contributor
timestamp: July 21, 2016, 12:38:34 pm
content: scope with SELECTABLE isolated channels.Small board, low speed signals (in the Hz order) i don't want to tie all grounds together when i could just rely on scope earthMore scopes with battery options.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: July 21, 2016, 12:48:20 pm
content: Quote from: ralphrmartin on July 21, 2016, 12:02:09 pmThat's a clamp-style current probe. Perfect for measuring amps coming out of an alternator, not so perfect for measuring microamps going into a microcontroller. Unless the technology has gotten dramatically better since last I looked?

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: July 21, 2016, 03:50:01 pm
content: Quote from: A.Huggy on July 21, 2016, 12:29:30 pmYou should be able to find a used Agilent/Keysight DSO6014A (older model) for around $2k. Or if you're lucky maybe a 3000A or 3000T. eBay or Craigslist...

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 21, 2016, 04:05:27 pm
content: Why not just use an external logic analyzer to decode the CAN protocol? Much cheaper!

author: bitslice
author_rank: Frequent Contributor
timestamp: July 21, 2016, 04:18:25 pm
content: Quote from: A.Huggy on July 21, 2016, 12:29:30 pmPC Interface for the CAN Bushttps://www.elektormagazine.com/magazine/elektor-200006/16774I think this may have had some kind of decoding ability?

author: wraper
author_rank: Unknown
timestamp: July 21, 2016, 04:48:24 pm
content: Quote from: A.Huggy on July 21, 2016, 12:29:30 pmGW instek GDS-2000E series, starting at $860 for 4ch 70Mhz version, $1,174 for 200MHz (decoding is already there, no need to hack).

author: pascal_sweden
author_rank: Super Contributor
timestamp: July 21, 2016, 05:05:09 pm
content: Regarding GW-Instek GDS-2000E series: Can the 70 MHz version be "upgraded" to the 200 MHz version?

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: July 21, 2016, 08:15:30 pm
content: Quote from: jjoonathan on July 21, 2016, 12:48:20 pmI've got a nice little clamp meter that will read DC / AC mA down to 1 mA. It's not an oscilloscope probe, and it doesn't read microamps, I agree.

author: wraper
author_rank: Unknown
timestamp: July 21, 2016, 08:21:28 pm
content: Quote from: pascal_sweden on July 21, 2016, 05:05:09 pmSo far no. Thought price difference between the models is is not that high as with most of the other scopes. 100 MHz version is pointless IMO as costs almost like 200MHz one.

author: C
author_rank: Super Contributor
timestamp: July 21, 2016, 08:33:45 pm
content: Quote from: tautech on July 21, 2016, 04:19:29 amtautechHow much of electronics today is built in a way to make limited test equipment usable?Why is the last stage before a high speed ADC a differential stage?What all changes when you go to fully differential circuits?Use a simple thought process. Go back to point to point wire even for power. Now change all the wires to have some resistance.Look at what you have.Fully Differential Output:First you should note an output is no longer using one of the power wires to change it's output and the signal is not using one of the power wires for a return path. When power is needed to change the outputs, equal power is needed from each power wire. Your power bypass cap becomes part of a low pass filter and no longer a coupler of noise on one power wire to the other power wire.Differential input:Look at the inputs. The load is between the two output signals. If you use two resistors as a load then the center tap is the center of the signal. No this center tap should not be directly connected to center of power. When the differential input becomes more single ended a signal starts appearing here. You really want the average of this point to be the center of power, a high resistance low pass. Here a single ended output with two resistors to power allow slow correction of power center if power is floating.There is a cost to do Fully Differential and a lot of gains.At the very low level the difference between P & N types is compensated for with difference between outputs correct while the center of the outputs change with respect to power center.You need to look at Fully Differential as the difference between outputs and not as two single ended outputs.The sad thing is Fully Differential existed back in the tube and transistor days.

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2016, 09:24:57 pm
content: Quote from: C on July 21, 2016, 08:33:45 pmThanks.While there are particular difficulties in isolated channel front end design it can be done and is.A recent vid Dave did examined the isolated frontend in some detail.There are several HH options available currently, but there are zero modern benchtop DSO's with isolated channels.Once upon a time they were commonly called Power scopes and those I've seen were in uni labs for the instruction of 3 phase power electronics. Tell me that's not taught anymore.Tell me a well designed scope with 4 isolated channels can't be offered to the market for less that a currently available DSO plus the cost of 4 differential probes.

author: nctnico
author_rank: Super Contributor
timestamp: July 21, 2016, 10:20:56 pm
content: Quote from: A.Huggy on July 21, 2016, 12:29:30 pmGW Instek GDS2000E series to the resque again! I had the same requirement and the GDS2000E series does CAN decoding very well.I also second the suggestion for a low cost isolation amplifier. I'm working on one (schematics for prototype ready) but need some spare time to burn on this project to see if my idea works or not.

author: David Hess
author_rank: Super Contributor
timestamp: July 21, 2016, 11:29:55 pm
content: Quote from: tautech on July 21, 2016, 09:24:57 pmDoes the Tektronix TPS2000 count.http://www.tek.com/oscilloscope/tps2000QuoteI doubt the high price of high voltage differential probes reflects the cost of design and manufacturing. I have never seen an hobby level one so the market must be very limited.I actually outlined what would be needed to hack together a limited performance and bandwidth one (below 20 MHz) using standard x10 probes a couple days ago for someone.

author: Someone
author_rank: Super Contributor
timestamp: July 22, 2016, 01:28:43 am
content: Quote from: David Hess on July 21, 2016, 11:29:55 pmFor all the hate the TPS2000 is a quality little unit, old fashioned but the lack of competition in that area of isolated channel scopes shows just how small and undemanding the market it.Quote from: David Hess on July 21, 2016, 11:29:55 pmThere is an example differential probe here:https://www.eevblog.com/forum/projects/diy-100mhz-differential-probe/Its configured for ?300V RMS input limited by dissipation in the DC divider, but the design is scalable in both directions to higher or lower voltages with more or less gain, getting lower noise needs a discrete FET input design but the most time consuming part was mating to the active probe interfaces and sourcing a suitable multi conductor cable.

author: tautech
author_rank: Super Contributor
timestamp: July 22, 2016, 02:15:27 am
content: Quote from: David Hess on July 21, 2016, 11:29:55 pmIt did 20 years ago but today with 2.5Kpts of memory depth it's a joke.So I'll highlight my statement above. ^^^Quote from: David Hess on July 21, 2016, 11:29:55 pmOf course not.Currently we have every conceivablefeatureadded to modern DSO's except arguably the greatest feature that would promotesimplicity and ease of use. Channel to channel reference and Ground isolation.Hell, even a reasonable bench DMM provides for 500V+ of isolation from mains. (Voltage Bias offset)QuoteThe absence of cheap differential probe adds additional cost to scope users that need one and that cost should NOT exist for want of a slightly more expensive isolated channel modern DSO.All of us at some time have needed/wanted isolation for the signal reference (Gnd clip/lead), haven't you?IMO this is an opportunity for some manufacturer tocreatea market demand, such are the benefits of simplicity and ease of use.

author: C
author_rank: Super Contributor
timestamp: July 22, 2016, 02:56:59 am
content: Is an isolated device or channel the same as a differential input device?Why not test and see if they are.You may have a bunch of isolated devices. Your DMM for example.To test, you just need a signal generator or function generator with the higher frequencies showing more. Protect the output with a series resistor of the output impedance.So you have signal generator on one side of resistor with scope and one lead of isolated device on other side.Look at scope while changing frequency from low to high with following.1. No device connected to resistor.2. DMM negative lead connected to resistor.3. DMM positive lead connected to resistor.Are all three steps the same?#3 is like one input of something with differential inputs

author: tautech
author_rank: Super Contributor
timestamp: July 22, 2016, 03:13:50 am
content: Quote from: C on July 22, 2016, 02:56:59 amOther than my bench DMM all my equipment is Gnd referenced, just as most test equipment is.Commonly used terminology adds confusion to general understanding, in particular mention of the Gnd leads on scope probes that are indeed common with mains ground on most scopes BUT should be correctly thought of as the signal reference lead.This is where what would be a simple connection for signal reference with an isolated DSO is entirely a different proposition with a Ground referenced DSO by way of NO risk of introducing ground loops if care is not taken to where the reference (Gnd) lead is connected on ordinary non-isolated scopes.A fully isolated scope overcomes this.EditsUnderstanding

author: JPortici
author_rank: Super Contributor
timestamp: July 22, 2016, 06:22:36 am
content: I have a tps2014 at work.Two things i love it for:- Lowest noise of all the scope we/i have- sturdy and lovely caseBoss bought it in the 00's to look inside cars because it was the best affordable isolated scope at that time and it still was about 3k€ or somethingBut it is so god damn slow and i always have to hope to set the trigger+timebase right for single time events otherwise i can only see what's in the screen...I'd much rather have a 1054z with battery power.... not really but, you know.. some modern perks like a decent amount of memory. still the fft and the X-Y mode are eons fasterI had considered going for a handheld scope like the new owons but the specs again are not that better than the TPS in regards of memory (what were those? 16k?) and to obtain battery powered scopes seems to have become impossible even though the technology is there as it has been for decades. what is it, a regulation problem? so the tps2000 is still king (sigh)

author: D3f1ant
author_rank: Frequent Contributor
timestamp: July 22, 2016, 06:30:16 am
content: Quote from: tautech on July 20, 2016, 09:23:51 pm+1

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: July 22, 2016, 08:21:56 am
content: Quote from: David Hess on July 21, 2016, 11:29:55 pmI'm going to pick up a couple of these when I am next in China, and see how they work out:https://world.taobao.com/item/38029768379.htm

author: tautech
author_rank: Super Contributor
timestamp: July 22, 2016, 11:53:53 am
content: Quote from: JPortici on July 22, 2016, 06:22:36 amDepressing isn't it.There are other/better HH choices however, the SHS1000 series and if you have deep pockets the R&S.http://www.siglentamerica.com/pdxx.aspx?id=93&T=2&tid=2

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2016, 02:45:35 pm
content: Quote from: tautech on July 22, 2016, 02:15:27 amThe isolation barrier imposes serious throughput limitations between the digitizer and processor so expanding the record length would come at the expense of record acquisition rate. The old Tektronix real time digitizer design was already low throughput making it a good match for this application.2.5 ksamples * 8 bits * 200 acquisitions per second = 4 Mbits/second

author: tggzzz
author_rank: Super Contributor
timestamp: July 22, 2016, 04:34:06 pm
content: Quote from: metrologist on July 20, 2016, 08:06:16 pmI'd ask them to produce a device that would tell me what's missing from the market.Can I have my $1 now, please.

author: tautech
author_rank: Super Contributor
timestamp: July 22, 2016, 08:15:39 pm
content: Quote from: David Hess on July 22, 2016, 02:45:35 pmThere have been significant advances in memory depth across input isolation from Tek TPS2k days as this post from early this year outlines:https://www.eevblog.com/forum/testgear/which-scope-with-isolated-inputs/msg839059/#msg839059Even the Siglent SHS1000 that I linked earlier has 2 Mpts memory depth and while these sorts of figures can't be called stunning by todays standards they are enough to be useful.