Gw INSTEK GOM-802 Precision Milli-Ohm Meter

[Terabyte2007]

I just received my GOM-802 Milli-Ohm bench meter today and I have to say this is a really nice unit. I have an ExTech Milli-Ohm meter which had a minimum resolution of .1 mOhm with a test current of 100mA. The GOM-802 has a 1 uOhm resolution and a test current of 1A on the lower milli-ohm setting which is wonderful for shunt measurements and design. Plus a full 5 digit resolution and settable Hi/Low test parms with alarms and a lot of other nice features included. If anyone is in the market for a high resolution Milli-Ohm meter, this seems to be a good choice. The Kelvin clips are very nice and seem to work well. The clips are much higher quality than the ones I have seen on eBay.

[tom66]

It looks nice, but I can't help but think with the number of 7-segment LEDs they fit on there, they could have put a proper LCD on there (graphic or not) -- or even a VFD -- it looks too cramped to me.

[Terabyte2007]

It looks nice, but I can't help but think with the number of 7-segment LEDs they fit on there, they could have put a proper LCD on there (graphic or not) -- or even a VFD -- it looks too cramped to me.

It could have been an engineering decision on cost, maybe even legacy, because older models seemed to have this type of display. Regardless, not a real show stopper for me. I do like the stability and accuracy, seems to be better than any other I have used so far. I do like the optional temp probe for temperature coefficient feedback measurements.

[dr.diesel]

Will have to research this against say a 510A.  I look forward to a possible video review?

[Terabyte2007]

Will have to research this against say a 510A.  I look forward to a possible video review?

I could probably manage that. If I can fit the time in for shooting it and some editing, maybe this weekend.

[dr.diesel]

It would sure be nice if they'd include offset compensation, which the Hioki RM3544 does not, or any of the others under $1000.

Does the 802 allow zeroing with sense active and source disabled/shorted?

[Terabyte2007]

It would sure be nice if they'd include offset compensation, which the Hioki RM3544 does not, or any of the others under $1000.

Does the 802 allow zeroing with sense active and source disabled/shorted?

Yes, I believe so. Esentially, using the REL functions should serve as an offset? Correct me if I'm wrong.

[robrenz]

Will have to research this against say a 510A.  I look forward to a possible video review?

Looks very respectable for the price

[robrenz]

It would sure be nice if they'd include offset compensation, which the Hioki RM3544 does not, or any of the others under $1000.

Does the 802 allow zeroing with sense active and source disabled/shorted?

Yes, I believe so. Esentially, using the REL functions should serve as an offset? Correct me if I'm wrong.

They are not the same thing. REL just subtracts out the value when REL was invoked from all subsequent readings. Offset compensation takes a reading of the sense leads voltage without test current flowing and subtracts that from the value with the test current flowing. This occurs every reading and removes the thermal emf errors from the reading. From a quick look at the manual it seem the GOM-802 only has REL

[Terabyte2007]

It would sure be nice if they'd include offset compensation, which the Hioki RM3544 does not, or any of the others under $1000.

Does the 802 allow zeroing with sense active and source disabled/shorted?

Yes, I believe so. Esentially, using the REL functions should serve as an offset? Correct me if I'm wrong.

Ok, good to know thanks.

They are not the same thing. REL just subtracts out the value when REL was invoked from all subsequent readings. Offset compensation takes a reading of the sense leads voltage without test current flowing and subtracts that from the value with the test current flowing. This occurs every reading and removes the thermal emf errors from the reading. From a quick look at the manual it seem the GOM-802 only has REL

[robrenz]

You can remove the thermal EMF of the measurement manually by taking a reading then switch the source leads at the  meter and take another reading and average the two readings.  Don't touch any of the measurement setup and tie the leads down close to the meter so you don't disturb anything when swapping the source leads. That is the only way you will get the accuracy spec. stated in the milliohm realm

[Terabyte2007]

You can remove the thermal EMF of the measurement manually by taking a reading then switch the source leads at the  meter and take another reading and average the two readings.  Don't touch any of the measurement setup and tie the leads down close to the meter so you don't disturb anything when swapping the source leads. That is the only way you will get the accuracy spec. stated in the milliohm realm

Thanks, makes sense.

[Ordinaryman1971]

Hello everyone, I have kind of a question about the same meter.. I have two of those. They are exactly the same besides of the ROM version in them... but on one of them the three screens on the left of the meter for the hi and low accuracy and the third one above them.. don't remember right now what's it's for are completely dark. The LCD display for measuring resistance is working fine, is as accurate as the other one I have. I have to add that when I turn the meter on it tests all the display during the "post" and they all lid up and seem to work fine, all the segments are ok, but when the "post" is finished the displays on the left of the meter go dark leaving the only resistance ON.
So, my question is... is it broken, is there an option on the meter itself, key combination, you turn those displays on and off with.
Anybody knows maybe how to access the schematics for this device so I can dig into it and find out what is going on.
And the last thing, yes I did read manual, no it doesn't mention anything that would give me a clue you can turn the displays on and off.
Anybody with the same experience, maybe you know the solution.
I mean, it's not the end of the world, I can still use the meter and it's a beautiful machine, I'm really happy with it but it annoys the heck out of me that I don't know how to approach the problem. 

[Terabyte2007]

Hello everyone, I have kind of a question about the same meter.. I have two of those. They are exactly the same besides of the ROM version in them... but on one of them the three screens on the left of the meter for the hi and low accuracy and the third one above them.. don't remember right now what's it's for are completely dark. The LCD display for measuring resistance is working fine, is as accurate as the other one I have. I have to add that when I turn the meter on it tests all the display during the "post" and they all lid up and seem to work fine, all the segments are ok, but when the "post" is finished the displays on the left of the meter go dark leaving the only resistance ON.
So, my question is... is it broken, is there an option on the meter itself, key combination, you turn those displays on and off with.
Anybody knows maybe how to access the schematics for this device so I can dig into it and find out what is going on.
And the last thing, yes I did read manual, no it doesn't mention anything that would give me a clue you can turn the displays on and off.
Anybody with the same experience, maybe you know the solution.
I mean, it's not the end of the world, I can still use the meter and it's a beautiful machine, I'm really happy with it but it annoys the heck out of me that I don't know how to approach the problem.

Interesting problem, I don't think it's normal for that to happen. I have never seen that on mine nor do I think any setting has ever produced that. Firmware maybe?

[Shock]

So, my question is... is it broken, is there an option on the meter itself, key combination, you turn those displays on and off with.

Follow the section in the manual about the "Compare Function" from start to finish. If you search and read the parts that have the keyword "Normal" it discusses how it works. But there are other sections that talk about enabling functions like switching the "Buzzer" on an off that uses that display as well.

I would say somethings messed up and if that doesn't get it working, I'd take it back to the place of purchase or if that can't be done contact the manufacturer.

[Ordinaryman1971]

I was thinking about the firmware. I'm going to copy the eprom from the other one and stick it in the malfunctioning one... lets see.
It still measures the resistance and does it pretty good so it's serving it's purpose, just when I look at it and I see the other one working fine... I can't stand it, "fix it" syndrome.

[Ordinaryman1971]

I've actually checked all the settings.. there is was, it was buried so deep I can't even recall the way I've done it but I was able to reset it and now all the displays are working correctly. All normal and up to spec. Thank you to all who replied to my question.