Unwell Fluke 1652

[EFLImpudence]

Apparently the start sequence is internal so you wont have noticed and in the Manual it says power up with no leads in.

Just to say, I did not know that and have never done it because I leave the leads in permanently when not in use and in the box.

 

[JohnW2]

Just to say, I did not know that and have never done it because I leave the leads in permanently when not in use and in the box.

I have to say that I can't find any mention in the manual to powering-up without leads plugged in.

I've just tried with the 'new' one and, as per my recollections, cannot see any differences between powering up with/without leads plugged in - if one powers up without leads, it displays "LEAd", but that then goes away as soon as one plugs the leads in.

The old one is currently 'in pieces', but I'll try with that ('just in case'!) when I have a moment.

Kind Regards, John

 

[333rocky333]

Just to say, I did not know that and have never done it because I leave the leads in permanently when not in use and in the box.

I only read it on the net, it may NOT be true, as I do not have the instruction manual, though it could explain the need for it too monitor the leads are in.

 

[333rocky333]

Page 43 apparently says a bit about it skipping a test.
I dont really like linking to rival forums but 4th october post

http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=11060

 

[EFLImpudence]

Will it work if the fuse is blown???

 

[JohnW2]

Page 43 apparently says a bit about it skipping a test.
I dont really like linking to rival forums but 4th october post

Ah, that's a fuse test (which is skipped if one powers up with the leads plugged in) ...

A fuse test is performed each time you turn on the tester. If leads are plugged into the L and PE terminals, the fuse test is skipped. If a blown fuse is detected, testing is disabled, FUSE appears on the primary display, and the tester issues a warning beep

Kind Regards, John
Edit: Dammit - too slow again

 

[JohnW2]

Will it work if the fuse is blown???

Quite. It sounds crazy!

Kind Regards, John

 

[SimonH2]

I'm still a bit confused by whatever you're suggesting. This machine obviously does not offer 4-point testing.

I only offered as a suggestion that they may be trying to go 4 point as far as is practical - which is to the point where the leads are plugged in. Not likely, just one possibility. It would allow them to compensate for internal resistances etc.

... and the simplest answer would probably be that they split the sockets so that they could test to see whether the leads had been plugged in (for whatever reason!)!

Indeed.

As I said before, the one situation in which failure to plug in the leads could cause misleading (and potentially 'dangerous') results would be when measuring IR - since an apparently reassuring display of ">500MΩ" could simply mean that one had forgotten to plug in the leads - and I suppose there is also a danger if one used the machine to 'test for dead' on its voltage range (without 'proving' it) without leads plugged in! With any other measurement, there is no 'danger' - low resistance ('continuity') would display ">2000Ω" with no leads connected and attempts to measure loop impedance or to undertake RCD tests without leads connected merely results in the machine beeping at you!

But all those reasons also apply to not properly connecting the other end of the leads - or having broken leads. Given that there is a requirement for a certain level of skill, it's hard to see why an operator not plugging in the test leads to the box (the easiest and most obvious error to spot) should be considered so likely while the other errors aren't.

Does seem odd, other than someone thought "we can so we will"

 

[JohnW2]

I only offered as a suggestion that they may be trying to go 4 point as far as is practical - which is to the point where the leads are plugged in. Not likely, just one possibility. It would allow them to compensate for internal resistances etc.

Fair enough, but I still don't really understand. The 'internal resistances' are not going to change, and 'adjustments to compensate for them' will presumably have been undertaken at initial 'calibration' (and at subsequent calibrations, should anything somehow change)

But all those reasons also apply to not properly connecting the other end of the leads - or having broken leads.

Quite so - which is why I don't really think that it would make sense for them to feel that such reasons justified including a test for the presence of leads.

Although, to my mind, far from a sensible reason for the test, Rocky has now brought our attention to one effect of not plugging in the leads - if one powers up the machine without leads plugs in, it undertakes an initial 'fuse test', but it doesn't do that test if it detects leads. Does that make any sense to you?

Given that there is a requirement for a certain level of skill, it's hard to see why an operator not plugging in the test leads to the box (the easiest and most obvious error to spot) should be considered so likely while the other errors aren't.

Indeed. However, like most such things, it has various bits of idiot-proofing built in - i.e. it will not attempt to neasure resistance if it detects voltage between the leads.

Kind Regards, John

 

[JohnW2]

Page 43 apparently says a bit about it skipping a test.

Now you have brought to our attention the fact that, for some extraordinary reason, the initial 'fuse test' is skipped if one powers up with leads plugged in, that goes a little way to explaining why I found different behaviour with/without leads when I 'simulated fuse failures' (by removing them) ....

Ah, it's actually more complicated than I previously described. ... If a lead is plugged into the L socket, the "LEAd" message appears on power-up, regardless of whether or not the 'internal' fuse is in place.

If no lead is plugged into the L socket, with the internal fuse in place, one again gets the "LEAd" message. However if (with no lead plugged in) one removes the internal fuse, one gets the "Err1" message. It takes about 1 second for that message to appear, and when it does appear there is an audible click of a relay operating. There is no such click when the internal fuse is present, whether or not a lead is plugged in (i.e. when I get the "LEAd" message).

I have now realised at least one reason why the internal fuse is 'hidden'. Since it's in series with the L-lead, and is in just a bare 'skeleton' fuse holder, it would be 'live' if an L-lead were plugged in and connected to the L of an installation. In contrast, the user-accessible fuse (in the 'battery compartment') is in series with the PE lead, and hence will usually be safe to touch. This illustrates another difference between the N and L+PE lead sockets - the N is not fused, but the other two are, and the fact that only L and PE ones have 'lead present detection' might be in some way related to this.

If I remove the PE fuse and then switch on, whether I have leads plugged in or not I still get the "LEAd" message (not the Err1 I get if I remove the L-fuse with leads unplugged). However, if I unplug the PE lead (but not if I unplug only the L-lead), I do get the 'relay click' which I get when the Err1 message appears (with L-fuse removed). You tell me

Kind Regards, John

 

[JohnW2]

Does seem odd, other than someone thought "we can so we will"

Yes, maybe. In relation to my previous cynical suggestion, what I have just posted (quotes from my earlier posts) makes me think of further scope for cynicism! ....

Both L and PE are fused, and I would have thought that both would be similarly likely to blow. If the PE fuse blows then, if one powers up without leads, the user is told of the failure and can replace the fuse himself/herself. If the L fuse blows, one gets an 'Err1' error message ('return to manufacturer for repair'), since that fuse is not accessible for user replacement. As I wrote before, one 'explanation' is that making a 'bare' L fuse (like the PE one) accessible for user replacement might be considered to be potentially 'dangerous' (for idiots). However, they would only have needed to spend a few pence for some sort of insulated fuse holder on the back panel to make that fuse also user-replaceable.

Am I getting too cynical in my old age?!

Kind Regards, John

 

[EFLImpudence]

I cannot think of anything further but was just thinking it odd that what seems to be a pointless feature is apparently the cause of the machine becoming unusable.

Also, you would think, if what the manual says is correct, then it would tell you to remove the leads when you switch it on so that it can do the fuse test.
Could it not do a fuse test whatever the lead situation?

It all seems quite bizarre.

 

[SimonH2]

... it has various bits of idiot-proofing built in - i.e. it will not attempt to neasure resistance if it detects voltage between the leads.

I'd class that as self preservation rather than idiot proofing. I recall many years ago that a small (analogue) multimeter didn't take too kindly to measuring the resistance of a 12V tractor battery (the battery won, the magic smoke was released from the meter) so being able to avoid such errors is a good thing.

Am I getting too cynical in my old age?!

I doubt it

 

[JohnW2]

I cannot think of anything further but was just thinking it odd that what seems to be a pointless feature is apparently the cause of the machine becoming unusable.

Indeed, as you will see if you look back, it was one of the first comments I made in this thread - not just 'odd', but exceedingly (or worse!) annoying, since I strongly suspect that the machine would probably still work totally satisfactorily if only the 'leads test' would allow it to! As I recently wrote, the problem could be circumnavigated if only they provided a means of disabling the 'leads test' (just as they seemingly do with the 'fuse test'!).

Also, you would think, if what the manual says is correct, then it would tell you to remove the leads when you switch it on so that it can do the fuse test.

One would expect that, given that doing an initial fuse test is not a bad idea.

Could it not do a fuse test whatever the lead situation?

Indeed. I have tried very hard but have not yet thought of any reason why it could not.

It all seems quite bizarre.

Totally!

Kind Regards, John

 

[333rocky333]

Could it be that when doing this fuse test the thing outputs a dangerous voltage, or that if the two leads are shorted together or even to the neutral, or even connected to a live supply, it messes up the test, or damages the meter, therefore easiest option is to detect if the leads are in, and if they are it knows then not to perform said test.