AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter

[floobydust]

From the user manual: "Do not input voltage exceeds 36VDC or 25VAC when you are at the setting of measuring current."
That number I believe is from the fake 61010 ratings.

[Nusa]

current range is limited to 36v - so no problem.

Limited by what?

Is there something preventing me from applying more than 36V to the current input? 

The instructions (the folded bit of paper that should have come with your meter) say "Do not input voltage exceeds 36V DC or 25V AC when you are at the setting of measuring current." Typical chinglish grammar, but the meaning is clear.

But no, there's nothing stopping you from applying more than 36V to the current input.

[TheUnnamedNewbie]

the fuses are only used for current reading, and current range is limited to 36v - so no problem.

If you only do what the manual tells you to do you won't ever need those fuses in the first place. They are there so that when something goes wrong, either due to a fault in what you are measuring or because of you being a human and making a mistake, the meter literally doesn't blow up in your face. Such mistakes could for instance be probing the wrong points and instead of measuring the current you suddenly put a large voltage across your meter.

[ebastler]

Is there something preventing me from applying more than 36V to the current input? 

Yes. It's verboten! 

[stj]

if your going to ignore the manual then nothing is stopping you from checking the ignition voltage at your spark plugs or taking it to a railway line to see if the extra rails are live!!

[stj]

btw, fun aside.

if you take the piss with the input voltage in current-mode you dont need to worry about the fuse because the Transorb suppressor will clamp-on and take the track off the switch.

i know this because i was given an 8002 for free after it happened to someone else!

[solidhit]

Hi, I'm a new user and I would like to say a big thanks to everyone since the pages of this forum are a goldmine for electronics enthusiasts like me.

That aside, I bought a new aneng 8008 and did the hardware updates suggested by jackenhack which really improved the meter.

Then I went on to modify my eeprom. Basically the only thing I needed was temperature, so I went on and added that to the mV range.

However, I don't have the calibration data (eeprom addresses 0x0B to 0x0F) and my meter is overshooting temperature. I know how I can modify addresses 0x0B, 0x0C to make the meter read lower, but since there's also the ADC value at addresses 0x0D to 0x0F, I'd rather copy these from an ANENG 8002 or ANENG 8009. Problem is, I looked everywhere for the eeprom contents of these meters and found nothing!

Could anyone help please?

[Mr. Scram]

Limited by what?

Is there something preventing me from applying more than 36V to the current input? 

Dave gon' get you.

[stj]

Hi, I'm a new user and I would like to say a big thanks to everyone since the pages of this forum are a goldmine for electronics enthusiasts like me.

That aside, I bought a new aneng 8008 and did the hardware updates suggested by jackenhack which really improved the meter.

Then I went on to modify my eeprom. Basically the only thing I needed was temperature, so I went on and added that to the mV range.

However, I don't have the calibration data (eeprom addresses 0x0B to 0x0F) and my meter is overshooting temperature. I know how I can modify addresses 0x0B, 0x0C to make the meter read lower, but since there's also the DAC value at addresses 0x0D to 0x0F, I'd rather copy these from an ANENG 8002 or ANENG 8009. Problem is, I looked everywhere for the eeprom contents of these meters and found nothing!

Could anyone help please?

8002 (3 different ones)
FA 00 C0 CE 03
E6 00 00 BD 03
F0 00 48 CE 03

8008
FA 00 00 BE 03 < this is the default value in the datasheet.

[solidhit]

Thank you so much stj, I will use these data to calibrate my meter and let you know how it went. Interesting thing though how you have three different versions of data for the same meter (hardware).

[stj]

that's why it's called "calibration" 

[solidhit]

All right, my meter is now calibrated temperature-wise.

FYI, I used "FA 00 C0 CE 03" . "F0 00 48 CE 03" works as well. "E6 00 00 BD 03" results in overshoot +5 degrees C.

Once again, thank you very much stj for your kind interest.

[solidhit]

There is one last thing I want to do before I leave my AN8008 alone.

There is some missing functionality button-wise:

RANGE - There already is a range button but it doesn't work as it should, I want a separate button.
MIN/MAX - That's very useful to have.
REL - This is necessary to turn on serial communication. I've already set eeprom address 0xFA to value 0xCE to allow that.

I will need to make a few holes to add these buttons as well as one for the comm. wires (I don't want infrared leds) but I've already figured out the best way to do that on the meter case thanks to our friends in the various Russian forums.

Now, this is were I get confused and need your help.

This is the diagram I use to understand how the DMM processor is connected to the pcb:
https://media.licdn.com/mpr/mpr/AAIA_wDGAAAAAQAAAAAAAAqmAAAAJDA3Nzc5MDhiLTliZjMtNGY0Zi05OTcwLWExZjY2ZjU4YTczYg.jpg

Questions:

• I notice how the buttons are connected to the processor and I come to the conclusion that if for example I want to let the processor know that MIN/MAX was pressed all I have to do is to temporarily connect PIN 23 (PT1.1) to PIN 26 (PT3.7). Is it that simple or is there something else I'm missing?
• I can see that PIN 20 is my TX PIN which I can use to send data to my PC. But I can also see that PIN 21 is an RX PIN.  Do I need that?
• Finally, is there anyone who knows where the PTx.x PINS that have to do with the aforementioned buttons are located on the 8008 PCB? Since this is a COB chip, I reckon it's a bit of a guessing game to locate the pins you are interested in. I will also need to locate the TX PIN.

This button issue is confusing to me because for example on the top right of the PCB there are contacts for a button (I think it's supposed to be a RANGE button?) and all it does is nothing (connects PT1.1 to BATT-). Why do they have contacts for a button that seems to do nothing? Is there something I'm missing with the whole button setup?

I have also watched this video:


It's a Russian guy who mods a ZT102 (AN8002) meter to add buttons. The points on the PCB he marks on his video to get specific button functionality, don't do anything on my AN8008 but work fine on his meter. This confuses me even more!

I would appreciate any response to help clarify these things.

[stroma]

As far as I know additional buttons hack on AN8008 is not possible.
You can find more info on the topic reading previous posts in this thread.

I tested some button options for the AN8008.
SET/HOLD is PT1.0 - BAT-
RANGE/BackLight is PT1.2 - BAT-

These did not have any effect.
PT1.0 - PT1.1
PT1.0 - PT1.2
PT1.0 - SDA
PT1.1 - BAT-
PT1.1 - PT1.2
PT1.1 - SDA
PT1.2 - SDA

So no button hacks found. There are still some possible pins but I think all other button options are disabled in FW.
Only temperature  probe is hackable.

IMHO AN8002 is a better option for general use and AN8008 is only better in those small ranges.

[solidhit]

Thank you stroma (in Greek, this name means mattress!)

If the quote from plazma stands, this is great!

It means we can hack the eeprom to reactivate the disabled button functionality.

But all I have, is the translated (by Kerry Wong) datasheet of DTM0660 and in the eeprom analysis, I can't find anything that refers to enabling/disabling such buttons!

EDIT: I wonder if it's the DM1106EN (used in an8008, improved DTM0660) that allows enabling/disabling button functionality. The ZT102 uses the DTM0660. I could find no datasheet for DM1106EN anywhere.

EDIT2: I spent many hours bombarding undocumented eeprom addresses with all sort of data to see if that changes anything towards making the various TPx.x points behave like in the ZT102 model. Nothing! If they limit the use of extra buttons, they must have done it in a different way. I don't know if this meter's CPU contains a firmware or not. I don't know if the limitation is in that firmware or there is something else on the PCB that makes the meter behave this way.

[Calambres]

Anyone know of a source for the 200mA 250V ceramic 10mm fast fuses for this meter?

I've ordered 10A spare fuses from ebay. Only found them with axial leads, to be cut off when needed:

https://www.ebay.com/itm/300757393643?ViewItem=&item=300757393643&ppid=PPX000608&cnac=ES&rsta=en_ES(en_ES)&cust=4R9279867B836642B&unptid=1c4da7f6-1c88-11e8-a9c9-441ea1479d80&t=&cal=7baed6587cd5&calc=7baed6587cd5&calf=7baed6587cd5&unp_tpcid=email-receipt-auction-payment&page=main:email&pgrp=main:email&e=op&mchn=em&s=ci&mail=sys


...but I cannot find the 200mA fuses anywhere except in Aliexpress:

https://es.aliexpress.com/store/product/10A-600uA-fuse-for-RM101-102-multimeter/909123_32811804077.html

but unfortunately they only sell them to you if you've bought the meter from them. Otherwise they won't sell the fuses. I bought the meter elsewhere...

[amspire]

You can get the fuses from the Richmeters store (exactly the same meters as Aneng), but ONLY if you have bought a multimeter from them:

https://www.aliexpress.com/store/product/10A-600uA-fuse-for-RM101-102-multimeter/909123_32811804077.html

[Calambres]

Yeah, the same story... I bought the meter from banggood and they have no fuses for it 

[plazma]

Wasn't there some option for a through hole fuse which was perfect if you cut the wires?

[Calambres]

If you read carefully three posts above yours, that's exactly what I've ordered for the 10A fuses. The problem is that I cannot find them in a 200mA value...

[Fungus]

Wasn't there some option for a through hole fuse which was perfect if you cut the wires?

Yep.

If you read carefully three posts above yours, that's exactly what I've ordered for the 10A fuses. The problem is that I cannot find them in a 200mA value...

So get 250mA or whatever's the closest.

A 200mA fuse doesn't blow at exactly 201mA.

[Calambres]

Can't find 250mA either!


I find them in Slow Blow version but not Fast Blow as required.

[floobydust]

I just noticed this meter has a bug 
AC mA reads zero until over 3.5mA and then reads 20% low, until over 10mA where it starts to read accurately. This is with 60Hz AC sine.

[exe]

Can't find 250mA either!

May be there is enough space for a regular fuse?

I think I saw these fuses on AliExpress, although the price was quite high.

[David Hess]

Here is a brute force method that I randomly came across in the LT1011 datasheet.  The LT1011 is an improved 311 but a couple of FET buffers and a better comparator could be used for even greater performance.