Continuity vs resistance test with DMM beep sound test function ?

[schiker]

When doing circuit diagnostics for a complete path when does it switch from continuity to an resistance test for a typical DMM?


When using a DMM for determining circuit paths....
Simple pole switch test or same wire test I use continuity test and you can hear a beep if on that function.

But when going over resistances ie a small coil or incadescent light it won't beep because there is a resistance between the two points. Is there a typical ohm value that DMM's quit beeping? I usually use a craftsman DMM and sometimes a Fluke. But is there a general rule. Probably depends on the test voltage of the meter and or battery strength of meter but again is there a typical max ohm value considered continuity?

 

[schiker]

Should have googled before one source said under 210 ohms should beep I think it was for a fluke 79 ???

Anyone else have some typical numbers.

 

[schiker]

I have been looking more and don't see a clear definition of range for ohms vs continuity. I guess I can use a potentiometer and vary resistance to see what max ohm value my meter will beep.

 

[Turbine Doc]

some of the meters have a selectable beep function, if just reading continuity you really aren't resistance checking. What kind of test are you trying to do?

 

[whatnot]

I can't find the fluke meter right now but just checked a couple Greenlee dmms (different models) and a radio shack dmm. One of the Greenlees and the radio shack were between 35 and 40 ohms. The Other Greenlnee was 85 ohms.

 

[NVW]

IIRC my Fluke will switch to ohms when it senses resistance while in continuity setting.

 

[schiker]

IIRC my Fluke will switch to ohms when it senses resistance while in continuity setting.

Nice feature.

Sorry for not finishing thread... I need to subscribe to some of my obscure threads as I forget to check them sometimes.

This was for my general understanding and future reference info for clarity when doing checks diagnostics etc so I don't do a similar mistake again.

Over the summer I was taking a motor controls class and chased a ghost (or what I thought was a problem but wasn't) for 45 minutes. I had finished my lab and was helping someone else. I put my meter up and was using thiers. I did not understanding why a Fluke meter beeped when I was checking "continuity" from X1 of control transformer to A1 on motor starter coil even though I had not pushed the start button and stop button did not stop beep either. My craftsman meter won't beep for this test usually until I push start and quits when I push stop.

This was on part of control circuit NC stop, NO start, paralleled with memory latch to motor starter. Also had a control relay and light and another stop and start station. Again my craftsman won't beep until I push start on similar tests. Thier circuit did not work so I shut it down and started probing. I found a few problems. But before rehooking power I wanted to check overall function. But the Fluke beeped continuity X1 to A1. And I thought they had another miswire issue so I probed and tested for 45 minutes not finding anything else. They did have several issues and fixed them early but this beeping worried me as the wiring was a jumble and I did not want to rehook power until I knew it was correct.

My craftsman meter quits beeping after something around 60 ish ohms iirc. The fluke would beep upwards of 100 ohms. What was happening was fluke was reading across A1-A2 then through 95-96 overloads to X2 back through control step down transformer coil back across from X2 to X1 a continuous path of 100 ish? ohms through coils ( can't remember the value) from x1 to a1 "backwards" not through the stop start buttons. And I mistakenly thought their stop/start buttons were not working correctly or a terminal or relay was miswired. Again My meter would not beep and it was easy for me to test my circuits start/stop button functions with meter probes tied from x1 on transformer to A1 motor starter.

Live and learn .... Continuity beep / ohm range means different things to different meters and different situations/circuits. And it helped me see clearer the loop of current on the control transformer loop.

Another situation was I picked up a non marked motor starter and was probing for terminals A1 - A2 and the my meter was on continuity beep but it did not beep on what should have been the coil this baffled me somewhat as I thought the coil should have beeped since it was just one small coil.