Author Topic: Analog meter advantages?  (Read 28301 times)

0 Members and 1 Guest are viewing this topic.

Offline rdl

  • Super Contributor
  • ***
  • Posts: 3665
  • Country: us
Re: Analog meter advantages?
« Reply #75 on: April 06, 2016, 04:56:13 pm »
When a signal tends to be relatively steady and its actual value needs to known, digital displays are better.

When a signal tends to vary and you need to know how it is acting or trending, analog displays are better.
 

Online tggzzz

  • Super Contributor
  • ***
  • Posts: 19281
  • Country: gb
  • Numbers, not adjectives
    • Having fun doing more, with less
Re: Analog meter advantages?
« Reply #76 on: April 06, 2016, 04:58:44 pm »
I can't view yout picture, but there is a picture, from the internet, of the Bombardiers CRJ-900ER NG (CL-600-2D24) cockpit while landing.
http://cdn-www.airliners.net/aviation-photos/photos/8/3/8/1855838.jpg
There are at least 9 analog displays...
But they don't have a scale. The value is digital displayed.

Good luck trying to fly an aircraft with an artificial horizon where the angle is displayed only in digits. Make sure you have made your will before you attempt it.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online tggzzz

  • Super Contributor
  • ***
  • Posts: 19281
  • Country: gb
  • Numbers, not adjectives
    • Having fun doing more, with less
Re: Analog meter advantages?
« Reply #77 on: April 06, 2016, 05:05:55 pm »
I can't view yout picture, but there is a picture, from the internet, of the Bombardiers CRJ-900ER NG (CL-600-2D24) cockpit while landing.
http://cdn-www.airliners.net/aviation-photos/photos/8/3/8/1855838.jpg
There are at least 9 analog displays...
But they don't have a scale. The value is digital displayed.

They don't need a scale. It is sufficient to know that "vertical is good", "a bit left is OK", "far left needs correction".

OTOH seeing "318.65" probably isn't helpful, because it will take time you don't have to remember whether 300 is good, 400 is good, 500 is better etc. Now repeat that for all indicators.

And make sure you scan them all once a minute.

And scan them again when an alarm is sounding, to find out which is/are indicating the problems.

By the time you have done all that you are probably inside a lawn dart or barbecue.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline sync

  • Frequent Contributor
  • **
  • Posts: 799
  • Country: de
Re: Analog meter advantages?
« Reply #78 on: April 06, 2016, 05:16:24 pm »
Good luck trying to fly an aircraft with an artificial horizon where the angle is displayed only in digits. Make sure you have made your will before you attempt it.
I talking about the displays in the middle which shows scalar values. The artificial horizon is a complex instrument and it's not comparable with an analog meter.
 

Offline rdl

  • Super Contributor
  • ***
  • Posts: 3665
  • Country: us
Re: Analog meter advantages?
« Reply #79 on: April 06, 2016, 05:51:41 pm »
I have no idea what those gauges are displaying and I can't even read the numbers actually, but the instant I looked at it I knew all was good.

...
I talking about the displays in the middle which shows scalar values.
...
 

Online tggzzz

  • Super Contributor
  • ***
  • Posts: 19281
  • Country: gb
  • Numbers, not adjectives
    • Having fun doing more, with less
Re: Analog meter advantages?
« Reply #80 on: April 06, 2016, 06:34:23 pm »
Good luck trying to fly an aircraft with an artificial horizon where the angle is displayed only in digits. Make sure you have made your will before you attempt it.
I talking about the displays in the middle which shows scalar values. The artificial horizon is a complex instrument and it's not comparable with an analog meter.

Nonsense.

The artificial horizon is a very simple instrument; it shows two angles, and that is all. Good luck trying to interpret a roll angle of 33 degrees, no 38 degrees, no 48 degrees.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline Hobby73Topic starter

  • Regular Contributor
  • *
  • Posts: 73
  • Country: us
Re: Analog meter advantages?
« Reply #81 on: April 06, 2016, 07:02:18 pm »
This is the OP ... thanks for all the spirited replies to my question.  On reflection, I was dead wrong about characterizing an analog meter as a legacy visualization format, as it's clearly the best choice for many use cases as you've provided examples for.
 

Online tggzzz

  • Super Contributor
  • ***
  • Posts: 19281
  • Country: gb
  • Numbers, not adjectives
    • Having fun doing more, with less
Re: Analog meter advantages?
« Reply #82 on: April 06, 2016, 08:03:05 pm »
This is the OP ... thanks for all the spirited replies to my question.  On reflection, I was dead wrong about characterizing an analog meter as a legacy visualization format, as it's clearly the best choice for many use cases as you've provided examples for.

Someone that listens, thinks, learns and changes their mind. Good to have you on the forum :)
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 
The following users thanked this post: Hobby73

Offline gb243

  • Contributor
  • Posts: 33
Re: Analog meter advantages?
« Reply #83 on: April 13, 2016, 07:00:12 am »
After reading posts in this thread I have ordered a new analogue multi meter. I have some circuits to 'tune for smoke' and remember doing so using both hands. One adjusts a trimmer for a local peak whilst the other hand sweeps back and forward to find if the peak is global or local. Rather like tuning a tube transmitter final. Doing this with an analogue meter is simplicity itself and I could do this quickly. Tuning for peak with a digital meter would take ages if not actually be impossible.

I have my Mastech and Fluke DMMs but whilst new analogue meters are still available I brought one. My resolution of not buying more test dear has yet again been broken.
 

Offline woodchips

  • Frequent Contributor
  • **
  • Posts: 590
  • Country: gb
Re: Analog meter advantages?
« Reply #84 on: April 14, 2016, 11:02:29 am »
An interesting question with many replies, just what a forum is for.

I think that two points have been missed.

Firstly, analogue meters were designed in the days when the manufacturer assumed that the person reading it actually wanted to see what value it indicated. So they provided a contrasting colour to the pointer and the scale, so they could be easily distinguished, at a glance, when not square on to the meter, in poor lighting. Now look at your LCD digital meter, grey on grey, limited viewing angle, not illuminated. Yes, you can get backlit ones but if you want a battery life it has to be turned off. My digital meters are all mains powered, with nice bright, easily viewable LED displays. Work a treat.

Secondly beware if measuring high frequency oscillators such as HV inverters, they can have a nastly habit of crisping digital meters. Presumably the leakage capacitance bypasses the series dropper resistors and blows the electronics up. No such problem with an analogue meter.

Slight digression, but when the BBC TV centre closed I bought a pile of the test equipment, and reading the manuals for items such as the 1781 and the WFM700 does indicate the difference between an analogue presentation and a digital, numerical, one.


 

Offline Tepe

  • Frequent Contributor
  • **
  • Posts: 572
  • Country: dk
Re: Analog meter advantages?
« Reply #85 on: April 14, 2016, 12:04:08 pm »
My principal experience is in aircraft that can and do fly higher than commercial airliners, are a damn sight prettier and more "sexy", and much more fun.

This looks sexier to me:
« Last Edit: April 14, 2016, 12:06:37 pm by Tepe »
 

Online tggzzz

  • Super Contributor
  • ***
  • Posts: 19281
  • Country: gb
  • Numbers, not adjectives
    • Having fun doing more, with less
Re: Analog meter advantages?
« Reply #86 on: April 14, 2016, 01:12:22 pm »
My principal experience is in aircraft that can and do fly higher than commercial airliners, are a damn sight prettier and more "sexy", and much more fun.
This looks sexier to me:

I'm more interested in doing than looking. And gliding is more extreme than most powered flying, in terms of height, G forces, acceleration, freedom, along ridges, and much more :)

OTOH, if merely looking is sufficient, then
https://www.museumofflight.org/aircraft/perlan-glider
http://www.whiteplanes.com/images/gliders/gliders42.jpg
http://flyinglessons.co.uk/wp-content/uploads/2015/05/glider-flight-%C2%A9-Aleksander-Markin-2012.jpg
looks much more sexy than
https://upload.wikimedia.org/wikipedia/commons/1/13/SAAF-Gripen-001.jpg
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline Rerouter

  • Super Contributor
  • ***
  • Posts: 4694
  • Country: au
  • Question Everything... Except This Statement
Re: Analog meter advantages?
« Reply #87 on: April 14, 2016, 01:41:12 pm »
There are 3 main types of analog movements from my background in automotive instrumentation,

first is a spring balanced galvanometer, its a coil, a counterweight and a hairspring to pull it back to zero with a tiny amount of force, this hairspring also dampens the meters response, general motion range is 270 degrees, but you can get to about 330 degrees if you really had to push it, if the bearing on the shaft are made out of quality material they can be surprisingly accurate, with almost no hysteresis, The cheaper mass produced ones will have no balance adjust on the middle of the shaft to fine tune the counter weight, and tend to use plastic bearings, in there use case they last and last, but they have about 1 degree of hysteresis (think holden VS commodore speedometer, yes even the police model)

Next up is a cross coil movement, these tend to be between 60 and 110 degrees of deflection, there very fast, to respond, with a deflection time under 0.5 seconds, its literally 2 coild crossed at an angle, older ones where not perpendicular, modern ones are, there is generally no hairspring and rely on the force applied to hold it firm, while the limited deflection range limits the amount of gravity it has to deflect against, in reality tilting them on there side on most will cause a reading change, its a reference coil and a signal coil, adjusting the ratio of currents changes the deflection, its non linear on most

Third and final is a sin / cos meter movement, these are similar to the cross coil, but are not range limited, and the winding are generally tilted over being straight up and down, these are the most common on modern dashes, some have hairsprings but most do not, these have an unlimited deflection range as you can spin them as many rotations as you please, there main downside is they are bistable, if you rotate the pointer 180 degrees from its current position it will remain and track from that position, and again rely on the large power being driven in to fight gravity, so they have a tendancy to read low at lower speeds, and higher at higher speeds, this is part of the reason why so many cars have expanded scales, if they had 110kmph at the dead end of the scale the movement would end up sitting closer to 118 at the far end, while its pointed dead up its pretty on the mark,

My favorite is the galvanometer type, as most you can easily tweak to be extremely linear and accurate, not to mention is the only type that tries to compensate for balancing issues, so that your speedometer doesn't gain 5kmph just by being on an incline,

Both digital and analog meters have there place, it comes down to how your using it, and to previous posts, most analog meter drivers until about 2002 where analog frequency to current converters, following the old KISS principle, for most of those it was cranking on flat batteries of mechanical issues that led them to needing repairs,
 

Offline sandos

  • Contributor
  • Posts: 14
Re: Analog meter advantages?
« Reply #88 on: April 15, 2016, 11:25:58 am »
My principal experience is in aircraft that can and do fly higher than commercial airliners, are a damn sight prettier and more "sexy", and much more fun.

This looks sexier to me:


Note the analog meters on the Gripen display! ;)

You can actually get much bigger views of these analog "steam gauges" on the displays if you want to. Also interesting: where are the backup instruments? Iv'e flown both A/B and C/D Gripen simulators and I had a really, really hard time to understand how they could remove the backup, analog instruments in C/D.... Turns out they have made the digital ditos as, or even more, redundant though, only it might not seem that way.
 

Offline Tepe

  • Frequent Contributor
  • **
  • Posts: 572
  • Country: dk
Re: Analog meter advantages?
« Reply #89 on: April 17, 2016, 08:15:56 pm »
Note the analog meters on the Gripen display! ;)
Without the parallax issues  :)
 

Offline Vtile

  • Super Contributor
  • ***
  • Posts: 1144
  • Country: fi
  • Ingineer
Re: Analog meter advantages?
« Reply #90 on: January 20, 2017, 08:08:52 pm »
Ok. This is old.. I skipped the page 2 and 3 when the aircraft display discussion started, sorry if I skipped something interesting or I'm repeating already said stuff.

I have both, while I haven't any voltnut ones in digital or analog (old Fluke and Megger are crown jewels in build quality).

I have three with analog meter movement, two of them are chopper FET input models (multitesters, FETVOM or alike) and handfull of 3½ digit DMMs in variety of grade. I have been thingking this same question in the past and I actually did buy my first anolog just to see what they were all about (then voltnuttery did bite a bit when I discovered the FET choppers.. Next stop is propably analog electrometer  :=\ ).  I come to conclution that the analog meter in jobs that do not need extreme measurement spectrum unlike measuring 1mV in 100 volts range, they indeed are more expressive if the scale is good and big enough.

In one evening when I were sorting/pairing my 0.1% resistors with bridge and a one of those choppers and chasing down all temp and ghost errors of the setup (with 10x instrumentation amplifier my meter would be on 5nV per scalemark and hundrets of picovolts eyeballing ::) ). This subject did jump to my head again, why the needle movement is so expressive. I finally did arrive to conclusion during that evening that it is not the 0..100% movement through the scale, but the actual change of the angle of the needle combined to that scaled movement that makes the difference. It is like looking throuh the straight line of vertical poles and you just notice the ones that aren't on line. While bargraph might show fluctuation they are still one dimensional, while needle with changing angle have more than one, like polar/vector graph.
« Last Edit: January 20, 2017, 08:50:37 pm by Vtile »
 

Offline rstofer

  • Super Contributor
  • ***
  • Posts: 9886
  • Country: us
Re: Analog meter advantages?
« Reply #91 on: January 20, 2017, 08:40:45 pm »
Analog done right:

http://www.avsim.com/pages/0808/Justflight/5-1%20XJ824%20Instrument%20Panel.jpg

You can mount analog meters such that 'nominal' has the needle straight up.  Often you don't care about the absolute value, 'about' is all you need.  It may also be all you have time to process.
 

Offline Vtile

  • Super Contributor
  • ***
  • Posts: 1144
  • Country: fi
  • Ingineer
Re: Analog meter advantages?
« Reply #92 on: January 20, 2017, 08:48:44 pm »
Damn flying contraptions.  :popcorn:
 

Offline CatalinaWOW

  • Super Contributor
  • ***
  • Posts: 5173
  • Country: us
Re: Analog meter advantages?
« Reply #93 on: January 20, 2017, 08:55:08 pm »
Old thread, but one advantage of analog meters that was overlooked last time is that they don't require a power supply.  I have 50 year old meters that can still measure voltage and current without any maintenance.  (I will grant that the ohms measurements don't work).

I can't count the number of times I have pulled a digital meter out of the bag and it was useless because the battery was dead and I didn't have a spare at hand.  It is worst on meters that have a push button on/off with no shut-down timer.  Second worst on meters with a slide switch or rotary dial for power with no shut down timer.
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 26755
  • Country: nl
    • NCT Developments
Re: Analog meter advantages?
« Reply #94 on: January 20, 2017, 09:08:52 pm »
That is more like analog DMMs.
I have a bunch of power supplies with analog meters and I'd really like to exchange those with accurate digital meters. After reading this thread (partly) it seems a bar graph might be a good idea as well.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline rstofer

  • Super Contributor
  • ***
  • Posts: 9886
  • Country: us
Re: Analog meter advantages?
« Reply #95 on: January 20, 2017, 09:57:38 pm »
That is more like analog DMMs.
I have a bunch of power supplies with analog meters and I'd really like to exchange those with accurate digital meters. After reading this thread (partly) it seems a bar graph might be a good idea as well.

For several decades, the output from analog computers was displayed on a zero-center voltmeter and/or strip chart recorder.

I am in the process of using a couple of Adafruit multicolor bar graph displays to produce the same kind of output.  Zero volts is center and the bar will stack up or down as a function of voltage. I really think the analog nature of the display will be a lot more intuitive.
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 26755
  • Country: nl
    • NCT Developments
Re: Analog meter advantages?
« Reply #96 on: January 20, 2017, 10:25:10 pm »
The real advantage of analogue displays is it stops people obsessing over insignificant digits of precision.
You wouldn't say that if you ever worked on a battery powered gadget and used a power supply like the Agilent 66311B. It is capable of showing uA so you don't need another DMM to get an accurate current reading. I kinda got hooked onto that.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline cdev

  • Super Contributor
  • ***
  • !
  • Posts: 7350
  • Country: 00
Re: Analog meter advantages?
« Reply #97 on: January 20, 2017, 10:36:33 pm »
I prefer to have both around because in some situations movement of the meter deflection being movement will sometimes attract my attention more than the changing of digits. Also, sometimes you need to "tweak" something for highest or lowest value. Its not so frequently that this distinction is there so I usually use my UT-61e but once in awhile I find myself reaching for my analog VOM. I just like having the analog as an alternative.
"What the large print giveth, the small print taketh away."
 

Offline Macbeth

  • Super Contributor
  • ***
  • Posts: 2571
  • Country: gb
Re: Analog meter advantages?
« Reply #98 on: January 20, 2017, 10:41:54 pm »
The Rigol DP832 is a popular PSU around these parts. I would love to know if anyone has found the "analog" dial display has been useful at all vs the regular classic 3 column DP832 display? It even has a dedicated button for the useless dials.




ETA: I could only find the "Hello Kitty" DP832A version of the dials on google image search. The regular DP832 version is the same but in monochrome.
« Last Edit: January 20, 2017, 10:45:01 pm by Macbeth »
 

Offline PA4TIM

  • Super Contributor
  • ***
  • Posts: 1161
  • Country: nl
  • instruments are like rabbits, they multiply fast
    • PA4TIMs shelter for orphan measurement stuff
Re: Analog meter advantages?
« Reply #99 on: January 21, 2017, 01:24:35 am »
I love to play with my analog meters. Most are far from precise but I have 3 that are very good. A beautifull small Pantec Dolimiti I got from a good friend complete with original probes and box. I had to repair it but the result is a meter that is spot on all over the scale. With the mirrored scale I can read it with a very good resolution.
The second an old Philips PM2502, almost perfect, except resistance measurement. And a beautiful Simpson 260 in original leather carry-case. Not as good as the Pantec but it comes close.
Besides these I have much more analog meters, passive, active, FETs, tubes, electrometers etc

Sometimes I use them while repairing old instruments of my own and just for fun. But after such a session I am grateful to have DMMs.

- Analog meters are often not very accurate
- The load your DUT much more as the avarage DMM
- They are very slow compared to the 2 DMM's I use daily (Keithley 2000 and a U1252A from Agilent
- No autorange
- They only do I, V, R. Some can do C and L but you then need an external voltage sourcre. I have one that has a (fast) continuity beeper.
- some have strange spaced scales that are very hard to read unless you use them daily.   I have seen a meter that has a range but no scale for that. You have to multiply the reading by 2.
- some use hard to find batteries.
- Often the reading changes if you change the orientation
- Static displays
- No hold

Avantages
- often beautiful
- I have some meters that have a resettable fuse. (like the Pantec and my AVO8's)

I would love to have an accurate active analog+digital meter that has a Diode testfunction,  continuity beeper (with ohm reading and led indication). TRMS, illuminated scale, capacitance and fast with a hold function.  Also with autorange

-


www.pa4tim.nl my collection measurement gear and experiments Also lots of info about network analyse
www.schneiderelectronicsrepair.nl  repair of test and calibration equipment
https://www.youtube.com/user/pa4tim my youtube channel
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf