Seriously, anyone know the story and meaning of "OL" on multimeters? - Page 1
Forum section: electronics / general

author: TheAmmoniacal
author_rank: Unknown
timestamp: November 03, 2018, 11:09:11 am
content: It's used on every multimeter - yet everyone calls it something different. What is it?

author: The Soulman
author_rank: Super Contributor
timestamp: November 03, 2018, 11:16:54 am
content: Imho its over limit, better would be out of range.

author: VK3DRB
author_rank: Super Contributor
timestamp: November 03, 2018, 12:52:06 pm
content: I remember a rather boastful electronic engineer at IBM seeing OL on fluke DMM, saying something like "OL means the meter is faulty".OL is a defacto standard that works with seven segment displays quite nicely.We use a lot of defacto standards without thinking about it. One defacto standard I hate is SMD tantalum caps having the stripe as positive, yet on electrolytic caps it in negative. Who ever devised the tantalum "standard" needs to be removed from the gene pool. It is illogical, stupid and dangerous. I think many of us have been caught out with that once.

author: macboy
author_rank: Super Contributor
timestamp: November 03, 2018, 02:00:27 pm
content: I can't believe overload is leading the poll. A meter is decidedly not overloaded with an open circuit on resistance mode. The measurement however is certainly over limit. Over limit works for all modes.

author: xmo
author_rank: Regular Contributor
timestamp: November 03, 2018, 03:03:02 pm
content: macboy wrote: "I can't believe overload is leading the poll."------------------------------------------------------------------------It's probably the leader because that's what it means. At least according to what the manufacturers say in their manuals.Keysight: "OL - Overload (the reading exceeds the display range)"Fluke: "If the input signal is greater than the selected range can measure,the Meter displays overload"

author: Gyro
author_rank: Super Contributor
timestamp: November 03, 2018, 03:25:29 pm
content: Datron:- Overrange: "Is signified by a 1 being illuminated at the left of the normal display. 100% overrange permits a maximum display of 19999(9)."- Overload: "Results in blanking of the display* when measured value exceeds 100% Overrange."*(would be OL on other meters)

author: TheAmmoniacal
author_rank: Unknown
timestamp: November 03, 2018, 03:47:57 pm
content: An overload indicator does not really make sense on modern multimeters, and really only makes sense in voltage or current mode (?).I would guess the OL indication originates from back when voltmeters were resistive panel meters? An over-voltage condition would in this case cause it to overheat and potentially burn?I've just looked at a few manuals, both Keysight and Fluke do say overload.

author: Cyberdragon
author_rank: Super Contributor
timestamp: November 03, 2018, 06:47:31 pm
content: Early digital bench meters have red overload lamps on them.

author: Dubbie
author_rank: Unknown
timestamp: November 03, 2018, 07:33:58 pm
content: My Keysight meter says Overload on the screen when open circuit on ohms mode

author: pelule
author_rank: Frequent Contributor
timestamp: November 03, 2018, 08:03:53 pm
content: IMHO it's overload.ADCs in the past have been single- ord dual-slope types. A integrator is charged by input voltage (and for dual-slpe again discharges by the reference voltage) The charge time is counted and gives the display value (count).Thus exceeding the input range caused the integrator to be overcharged means overloaded./PeLuLe

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 03, 2018, 08:09:54 pm
content: It's obviously "Out of Luck".

author: wilfred
author_rank: Super Contributor
timestamp: November 04, 2018, 12:02:47 am
content: Quote from: VK3DRB on November 03, 2018, 12:52:06 pmRe SMD tantalum cap marking. Thanks for the warning. Only used through hole till now.

author: Feynman
author_rank: Regular Contributor
timestamp: November 04, 2018, 08:38:43 am
content: For me its always been "over load". Most multimeter manuals describe "OL" with something like "Overload condition is detected", e.g. the manual of the Fluke 87V.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 24, 2021, 11:31:17 am
content: While it may not make sense it means "Over Load" because the DMM manufacturers said so. I just wonder which DMM was first to display "OL". Early DMM display a 1 for this.

author: tom66
author_rank: Super Contributor
timestamp: April 24, 2021, 01:39:18 pm
content: I want to know why budget multimeters show a single "1" when in over-range. If the concern is over logic complexity, I can understand not wanting to implement text characters, but a single or double hyphen would probably be more understandable. So many times I've worked someone unfamiliar with multimeters through a problem and they've said things like, it reads "1 Volt" and then only do you realise that they had it on the mV range and that's the overload indication.

author: Neilm
author_rank: Super Contributor
timestamp: April 24, 2021, 06:01:29 pm
content: Surely it means "Oh Lord" - given I most often see it on a continuity reading and I now have an open circuit to find in a bunch of wires

author: Cyberdragon
author_rank: Super Contributor
timestamp: April 24, 2021, 06:24:12 pm
content: Quote from: BeBuLamar on April 24, 2021, 11:31:17 amNixie (or other early digital display) multimeters have indicator lights for "Over Load". I'm assuming LCD DMMs in the 80s soon followed.

author: bdunham7
author_rank: Super Contributor
timestamp: April 24, 2021, 06:26:22 pm
content: Some of them spell it out for you.

author: rfclown
author_rank: Frequent Contributor
timestamp: April 24, 2021, 06:54:36 pm
content: It isn't up for a vote. Read the manual.

author: TimFox
author_rank: Super Contributor
timestamp: April 24, 2021, 07:58:42 pm
content: I repeat the important bit mentioned above: "OL" works nicely on 7-segment displays, but "OR" is perhaps harder to read.

author: magic
author_rank: Super Contributor
timestamp: April 24, 2021, 09:16:44 pm
content: Quote from: tom66 on April 24, 2021, 01:39:18 pmThe answer is "because ICL7106"Now, what Intersil was smoking, ask them...

author: hans
author_rank: Super Contributor
timestamp: April 24, 2021, 09:20:29 pm
content: Quote from: macboy on November 03, 2018, 02:00:27 pmWell, if you consider an Ohms measurement using a CC, then overload could be applied (somewhat reciprocally) that the open circuit voltage is being exceeded.I agree over limit makes more sense, but my first intuition was that this terminology (among other generic terms) by chinglish translations.Nonetheless, there are more conventions that we carry over by tradition rather than common sense. Otherwise the whole world would be using metric by now, and we certainly wouldn't have 0.635mm SOP packages that look like 0.65mm

author: KE5FX
author_rank: Super Contributor
timestamp: April 24, 2021, 09:28:03 pm
content: Quote from: TimFox on April 24, 2021, 07:58:42 pmBut it's used even when 7-segment displays aren't. In addition to the Fluke above, the mainstream HPAK DMMs also display "Overload" with open probes in the resistance mode.It's especially weird because in continuity test mode, the default display is simply "OPEN." Why didn't they do that for resistance as well?

author: SpecialK
author_rank: Regular Contributor
timestamp: April 24, 2021, 09:32:45 pm
content: ∞ infinityComing from an analogue multimeter to an autoranging DMM I only ever really saw the OL in ohms mode. Luckily I've never measured voltage greater than the DMM could handle and I much less often measure current, usually I measure that from the bench power supply.

author: Cerebus
author_rank: Super Contributor
timestamp: April 24, 2021, 10:52:45 pm
content: Quote from: Mr. Scram on November 03, 2018, 08:09:54 pmNa, can't be that. The seven segment abbreviation of that would be 5.0.0.L. and they just put 0.L.

author: steve30
author_rank: Frequent Contributor
timestamp: April 26, 2021, 09:41:23 am
content: I've used meters that have said OFL which I always jokingly said could stand for 'Over F****ing Limit' as if the meter is annoyed at getting overloaded. Of course in reality it probably means Overflow.

author: themadhippy
author_rank: Super Contributor
timestamp: April 26, 2021, 11:06:36 am
content: Its actually an abbreviation for an ancient scottish phrase, "oot the lum" ,and relates to the fact if you continue smoke will flow.

author: SeanB
author_rank: Super Contributor
timestamp: April 26, 2021, 11:12:43 am
content: OL to say Over Range, because a 7 segment display historically is poor at showing alpha characters, so L is used instead of R, as L is unambiguous on the display, while the R can be confused with 8, A, B and cause confusion if a segment has failed.

author: vk6zgo
author_rank: Super Contributor
timestamp: April 26, 2021, 11:55:20 am
content: The very first digital meters were voltmeters.The only time they are likely to say "Overload" is if they are reading a voltage higher than the limit of the maximum range & hence, the max display reading they can produce.An analog meter will let you know in no uncertain manner, if you do this, as you will "twang" the meter pointer against the RH stop.A digital meter may "try" to display the over range voltage, & omit the leading figure, so OL gives you the equivalent of "twanging" the needle.When proper DMMs appeared, "OL" was pretty well unassailable.

author: ajb
author_rank: Super Contributor
timestamp: April 26, 2021, 10:29:48 pm
content: Keithley DMM6500 says "Overflow" when the leads are open in either resistance mode.

author: SofiaJoy
author_rank: Newbie
timestamp: October 11, 2023, 05:38:58 am
content: "OL" is often used as an abbreviation in various contexts to represent different meanings, as you mentioned. Here are a few common interpretations:Open Loop (OL):In control systems, an open loop refers to a system where the output is not influenced or corrected based on the system's performance. It means there is no feedback mechanism to adjust the system's behavior. This is commonly used in the context of control theory and automation.Overloaded (OL):In the context of electrical or electronic measurements, "OL" on a multimeter typically indicates that the measured quantity (such as voltage or current) is beyond the range or capacity of the multimeter. It suggests that the value being measured is too high for the instrument to handle.Over-Limit (OL):Similar to "overloaded," in the context of voltage and current measurements, "OL" can also stand for "over-limit," indicating that the measured value exceeds the limit of the measuring range of the instrument.Open Circuit (OL):In the context of electrical circuits, "OL" can indicate an open circuit. This means there is a discontinuity in the circuit, and it is not closed or completed, preventing the flow of electric current.The meaning of"OL"depends on the specific context in which it is used, so it's essential to consider the context to interpret it correctly.

author: Halcyon
author_rank: Unknown
timestamp: October 11, 2023, 05:43:29 am
content: ChatGPT much?

author: magic
author_rank: Super Contributor
timestamp: October 11, 2023, 07:31:59 am
content: Obvious spam is obvious. Look at the "personal link" in the profile

author: MarkS
author_rank: Unknown
timestamp: October 11, 2023, 05:26:46 pm
content: I come from a programming background. In C/C++, "0L" means 0 long words (4 bytes, 32 bits). It's primarily used in memory addressing to signify a NULL value to a pointer. As such, I have always read the OL as 'No Reading".

author: artag
author_rank: Super Contributor
timestamp: October 11, 2023, 09:47:17 pm
content: Quote from: magic on April 24, 2021, 09:16:44 pmGood answer.I suspect that the reason is that the logic in the meter ensured that above 1999, 1999 was still the result along with a status indication. Displaying something special like OL would require extra logic to provide that pattern on the display, and a separate LED would need both a pin and an LED to show it. Applying blanking to the lower digits probably needed very little logic and so was chosen.

author: EPAIII
author_rank: Super Contributor
timestamp: October 12, 2023, 06:18:51 am
content: I always thought of it that way. Perhaps I read an instruction manual or three.And the seven segment display rational makes sense. But so does the idea of a Voltage being too large for the device to handle. That is the classic definition of an OverLoad: too much of a load for the device to handle.Quote from: xmo on November 03, 2018, 03:03:02 pm

author: Psi
author_rank: Super Contributor
timestamp: October 12, 2023, 07:03:55 am
content: Outlandishly LargeWell.. it's either that or "Overcooked Lasagna"

author: AndyBeez
author_rank: Frequent Contributor
timestamp: October 12, 2023, 08:20:19 am
content: "Oh Lordy" or error code 70 upside down?My meter helpfully reads HI and L0Maybe "b5" for Blue Smoke?

author: pdenisowski
author_rank: Super Contributor
timestamp: October 12, 2023, 10:05:10 am
content: I wonder if Japanese multimeter manufacturers use "OL" (オーエル) on metershttps://dictionary.cambridge.org/dictionary/japanese-english/ol