Decent multimeter

[Yukster]

Now now boys and girls! let's keep the toys in the pram!!!

Big Tone; if you like dials and quality hifi than have a look at this amplifier

Untitled

• Yukster
• 28 Feb 2014
• 1

 

[Big Tone]

They're commonplace everywhere because they're cheap to manufacture, and that's all.

And versatile, and precise, and reliable, and durable..

I've never had a spurious reading from a needle or a segment go duff turning an 8 into a 9 or 3 or a 9 into 7 etc..

 

[Big Tone]

Boys and girls! let's keep the toys in the pram!!!

There's no right or wrong; just personal preference.

Hmmm... Dial porn

 

[Monkeh]

They're commonplace everywhere because they're cheap to manufacture, and that's all.

And versatile, and precise, and reliable, and durable..

I've never had a spurious reading from a needle or a segment go duff turning an 8 into a 9 or 3 or a 9 into 7 etc..

No, but I imagine you've read it wrong trying to get any resolution out of the things.

Not that there's any point in resolution with accuracy figures like 5% of full scale..

 

[Big Tone]

Yes, but for most purposes you don't need anything like that accuracy to such tolerances. Also, my old AVO had a mirror on the scale to help with parallax error. So you could, if you wished or really needed, get a very accurate reading. (If calibrated and set properly on zero).

Up until recently I was wearing a watch which is not a quartz movement. It lost about 5 minutes over a week but if I wanted I could have got it better with the tiny lever thingy and the + & - markings.

I think we, in modern society, feel we need this accurate clever stuff just because they can make it, we feel we need it and before you know it - it's the latest must have and anyone who doesn't follow is a dinosaur.

Still happy with my 23 year old Micra. Meanwhile, my ex wot is living with me and has just bought a new Fiat 500c is driven nuts by: -

"Beep" - Stick your belt on!
"Beep" - Ice warning
"Beep" - Petrol low
"Beep Beep Beep" - Fasten passenger seat belt. (No passenger. Just a laptop on the seat).
"Beep" Code 428. Has to look it up... Could be serious = Can do SFA about it = Take to Dealer = £££
"Beep/Flashing Idiot light". $ervice! (And only the Dealer can reset it = £££ s)

BW

T. Rex

 

[Monkeh]

Yes, but for most purposes you don't need anything like that accuracy to such tolerances.

And if, say, you wanted to determine if your house was supplied with ~230VAC or ~240VAC?

 

[Big Tone]

Yes, but for most purposes you don't need anything like that accuracy to such tolerances.

And if, say, you wanted to determine if your house was supplied with ~230VAC or ~240VAC?

I think you may have just made my point though bud. I was told a long time ago that it hasn't been 240v in my area for yonks and 230v is the norm. But did anyone know or care? Did our equipment stop working?

Can you put meat on your "if" because, like I say, knowing these things for most people is very much the exception, not the norm.

QED?

 

[Monkeh]

Yes, but for most purposes you don't need anything like that accuracy to such tolerances.

And if, say, you wanted to determine if your house was supplied with ~230VAC or ~240VAC?

I think you may have just made my point though bud. I was told a long time ago that it hasn't been 240v in my area for yonks and 230v is the norm. But did anyone know or care? Did our equipment stop working?

It matters for various calculations. One would assume that having a meter implies requiring information from it in order to perform a task.

How about the charge state of a car battery? Or the alternator float voltage? Being out by 1V either way is the difference between an uncharged battery, a good battery, and a fried battery.

Analog meters are certainly useful in some applications.. but simple reading of a stable value is not a task a modern, cheap one is remotely suited for. A well cared for Avometer is accurate enough to be of utility, however they're bulky, rare in good shape, and delicate (god help you if you drop one, especially if you've selected an undamped range).

Now if you want to be able to detect oscillation, especially slow, they're very handy. Digital meters jumping around don't convey the same message and the bar graphs are almost never accurate enough to be useful for that.

 

[Big Tone]

I thought you were going to be biased, but I give cred where due ta.

IIRC Fluke were the first, that I saw, introduce a bar on their meters to mimic the feel of a needle. (Mid 80s). But it still didn't have the same feel for me.

Bit like, to use another car analogy, the simple humble switch. Not simple anymore I can tell when I use the flash on Maria's Fiat it goes through a PIC and/or relay. There's a fraction of a delay while clever stuff thinks about it.

KISS please! It's unnecessary, more expensive, more complicated and us DIYers can't do a thing to fix it. (Deliberately so).

 

[Monkeh]

I thought you were going to be biased, but I give cred where due ta.

IIRC Fluke were the first, that I saw, introduce a bar on their meters to mimic the feel of a needle. (Mid 80s). But it still didn't have the same feel for me.

It's definitely not the same feel, but it is very handy in some situations. I've detected oscillation with them before, enough to make me go '.. huh, something's odd here' and get out an analog meter or a scope (which have similar voltage accuracy concerns as analog meters). On higher end meters, the bar graphs are much more versatile, and can be used for purposes such as maintaining a view of a live circuit with a held value, and seeing positive and negative swings in relative mode (and not just in resistance, like most analog meters, but for voltage, current, capacitance, frequency, duty cycle, temperature.. this is what I mean by flexibility).

Bit like, to use another car analogy, the simple humble switch. Not simple anymore I can tell when I use the flash on Maria's Fiat it goes through a PIC and/or relay. There's a fraction of a delay while clever stuff thinks about it.

KISS please! It's unnecessary, more expensive, more complicated and us DIYers can't do a thing to fix it. (Deliberately so).

In many modern vehicles, there is no relay operating the indicators or lights, and in fact, no special wiring. They run DC power and a data line out to each light cluster, and instruct a controller in the cluster to electronically switch individual lamps. There is a very slight delay to switch all this stuff on and off which may be perceptible.

On the other hand, it actually greatly simplifies things for the vehicle manufacturer. They no longer need complicated wiring harnesses, all testing can be done electronically, actions can be performed electronically which would otherwise require mechanical interaction. Features can be added to vehicles without requiring a change or addition to the wiring harness, and faults all around the vehicle can be identified and reported without requiring extensive inspection.

Yes, it adds complexity from the perspective of the user/owner, as they remain ignorant of the functionality, however, that is the nature of advancing technology. I rather like this system (vastly lower chance of wiring faults, for example), however, it is very awkward to interact as they keep all the fun stuff in proprietary protocols (and yes, a large part of that decision is to keep money flowing through their dealers, other issues relate to safety, and I suspect more than a little fear of criticism!).

 

[Big Tone]

Thanks again Monkeh.

I always remember a story of a pilot on a commercial airplane say over the tannoy "I'm sorry but there will be a short delay due to a technical difficulty. It's equivalent of pressing control alt delete".

Cars are going the same way, except if they conk out the consequences aren't as bad. Still annoying though.

Well, I've gone a bit off topic soz. Interesting spin off though

 

[Aragorn84]

In many modern vehicles, there is no relay operating the indicators or lights, and in fact, no special wiring. They run DC power and a data line out to each light cluster, and instruct a controller in the cluster to electronically switch individual lamps. There is a very slight delay to switch all this stuff on and off which may be perceptible.

On the other hand, it actually greatly simplifies things for the vehicle manufacturer. They no longer need complicated wiring harnesses, all testing can be done electronically, actions can be performed electronically which would otherwise require mechanical interaction. Features can be added to vehicles without requiring a change or addition to the wiring harness, and faults all around the vehicle can be identified and reported without requiring extensive inspection.

Yes, it adds complexity from the perspective of the user/owner, as they remain ignorant of the functionality, however, that is the nature of advancing technology. I rather like this system (vastly lower chance of wiring faults, for example), however, it is very awkward to interact as they keep all the fun stuff in proprietary protocols (and yes, a large part of that decision is to keep money flowing through their dealers, other issues relate to safety, and I suspect more than a little fear of criticism!).

I'm not sure it does simplify things? You've had to build and design a microcontroller for each lamp cluster which costs more than some simple lamp holders and some wire (and the lamp holders and wire are there anyway!) You've also had to design and build a controller inside the car which takes all the inputs from the stalks, processes them and combines them into a data signal and sends them to the microcontrollers out in the lights. Just like different models of car would previously have had different looms, you've now ended up with different microcontrollers for each type of light, ie the model with the HID steering headlamps will have a different controller to the model with the basic non-steering halogens.

You've also now got fragile electronics mounted in a hostile environment, rather than simply having some copper wires, which is not really good for reliability or longevity, especially with the crap solder they use these days.

Theres also now multiple points of failure. not only does the small posibility of a wire fault still exist (cept now one that will take out ALL the lights rather than only one) but you've added many additional components all of which are MORE likely to fail than some copper wire.

And ofcourse, after all that, they've made it MORE difficult to work on and repair because none of their clever systems are documented or using any standards. So whereas before, if the front left headlamp stopped working you'd have a simple diagram and some common sense steps to figure out where the fault is, you've now got a complicated mess.


While there is certainly some aspects of electronic control and diagnostics which is useful, they have IMO gone completely over the top with systems such as those described here for lighting. I LIKE the fact my engine ECU monitors all its sensors and provides me live outputs and in depth diagnostics. Its a complex system and would be difficult to fault find otherwise. It also conforms to various diagnostic standards meaning i can do the diagnostics with any device from a laptop, to a phone, all the way to a bespoke dealer diagnostic system. But lights? No thanks.

 

[bernardgreen]

When the steering lock on my car failed the engine control unit ( ECU ) refused to start the car. Hence a recovery service was needed to get the car home and then another trip to the main dealer.

The lock was OK. the fault was the communication port in the lock's micro-processor. Fortunately it failed in a super market car park. Had it been on a road in a remote location then the inconvenience and possible risks would have been much higher.

Older technology would have allowed the lock to be removed and a couple of wires joined to "cheat" the ECU into thinking the steering was unlocked. The the car could be driven to a safe place until a repair could be made.

Modern cars are designed for easy, fast and low cost assembly with little thought about ease and costs of repair and maintainance.

 

[Monkeh]

I'm not sure it does simplify things? You've had to build and design a microcontroller for each lamp cluster which costs more than some simple lamp holders and some wire (and the lamp holders and wire are there anyway!)

One-off cost. The modules are reusable, and not particularly complex. The wiring harness no longer needs individual wires for each lamp present, this simplifies it greatly.

You've also had to design and build a controller inside the car which takes all the inputs from the stalks, processes them and combines them into a data signal and sends them to the microcontrollers out in the lights. Just like different models of car would previously have had different looms, you've now ended up with different microcontrollers for each type of light, ie the model with the HID steering headlamps will have a different controller to the model with the basic non-steering halogens.

It's there anyway, and it's nothing but a software change to support other setups.

You've also now got fragile electronics mounted in a hostile environment, rather than simply having some copper wires, which is not really good for reliability or longevity, especially with the crap solder they use these days.

Not half as fragile as you might expect, and cars are exempt from RoHS.

 

[JohnW2]

Modern cars are designed for easy, fast and low cost assembly with little thought about ease and costs of repair and maintainance.

Very true - just as with a vast number of other products these days. Indeed, a very high proportion appear to be designed and manufactured on the basis that repair (other than, sometimes, 'module replacement') will never be attempted (or possible).

However, I don't think that one can really blame the manufacturers. It is their customers who, certainly in terms of mass-market products, demand and expect the cheapest possible product.

Kind Regards, John