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ADS1115 PROBLEMS
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 8:57 am

This is my circuit!! it is a current source (0-444mA) (i would like to measure current directly from any other device than this but i cant find current sensor with 16bits or more) all i do is taking voltage and change it to Current measurement devided by 5.6 on LCD reading
I connect the adafruit parallel of the resistor 5.6 Ohms

I made another test now in my last Adafruit ads1115 i had and the time i connected it on arduino with 12vdc was fine!! But as soon as i connected it to measure the voltage on the 5.6ohms resistor (potentiometer was giving me 0volts, 0amps), i had problem!! got destroyed again!!
Before i did the same with the arduino UNO taking Voltage from usb and everything was fine!!
Attachments
20170313_141744.jpg
My circuit
20170313_141744.jpg (253.39 KiB) Viewed 455 times

Stamos
 
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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 8:59 am

How do you have the ADS1115 connected? It is not in your diagram.
Please post a photo showing all your soldering and connections to the board.

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 9:42 am

I dont have the DS connected now, i put it out at the moment!! I measured The 5.6ohm Resistor
The board is functionable
Attachments
1.jpg
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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 9:48 am

We can't diagnose the problem with the ADS1115 if we can't even see how you have it connected.

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 10:53 am

Well i suspect you cant read what i write, i think you just only watch pictures and leave the notes unread...

Please i write it one more time and read it this time...

First of all... i have used the ADS1115 with arduino uno cinnection as it is supposed to be connected in differential mode with usb connection to USB.. i have normal measurements of the circuit that works properly...

THEN i try to make the whole project to work from the 12VDC Battery, AND i give 12VDC to arduino (ads1115 takes 5v from arduino same as LIQUID CRYSTAL)..
when i put the connectors PARALLEL to 5.6 ohms resistor the ADS gets DESTRYED.. AND didnt change anything else from the rest cirquit.. i just put the 12v to ARDUINO UNO input... SO thats my problem..

Stamos
 
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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 11:12 am

Well i suspect you cant read what i write, i think you just only watch pictures and leave the notes unread...

The Terms of Service for these forums includes a "Be Excellent To Each Other" policy. Please review that before posting.
https://www.adafruit.com/terms_of_service

The descriptions of your connections is not complete and does not tell us all we need to know. Please post photographs of your actual circuit - including all of your soldering and connections.

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 11:23 am

ye well, its a bit difficult to show you ADS1115 cause it is in recycle bin now.. and i cant help with photographs...

Well i am using the wrong device

Please if you have any idea if there is any sensor from adafruit that measures current directly with 16bits resolution or more, would be more helpfull than any other information

Thank you

Stamos
 
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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 11:52 am

Inputs to the ADS1115 need to be between GND and VCC (5v in your case). Not sure what the Vf of your laser is, but if your Arduino and ADS1115 are sharing a ground with the laser circuit, you would most likely need some additional circuitry like a resistor divider to scale the resistor voltages to a workable range.

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 12:17 pm

i sholdered on board a ground from the arduino to the board to take just seperate grounds and 5V... took an arduino Ground and 5v Vcc...
Now i am just thinkin to work as before to use USB as power source for the arduino from a Power bank... Its my diplomatic Project so i dont use really a laser but a 0.7Vf Diode.. and a 3.3V zener... (kirchhoff law if i got max current 450mA)

so i assure you that the grounds are seperate from the circuit and for ADS1115...
The problem only comes when i got 12V to arduino and i connect A0 AND A1 (differential mode) on 5.6ohms

when it is with usb, its working perfectly

Stamos
 
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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 12:22 pm

If the grounds of the ADS1115 and your circuit are separate, than what was the ground reference for your signals?
Without a ground reference, the signal voltage as seen by the ADS1115 is unpredictable.

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 3:39 pm

you mean to use same ground with the rest circuit of my curent source?

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 3:39 pm

want me to make a schemating on a papper and send you what i mean?

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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 4:08 pm

Yes, a schematic would be helpful.

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Re: ADS1115 PROBLEMS

by Stamos on Wed Jun 21, 2017 4:22 pm

Thats what i actualy did...
Attachments
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Re: ADS1115 PROBLEMS

by adafruit_support_bill on Wed Jun 21, 2017 4:41 pm

Connected like that, your Arduino is grounded to the negative terminal of the battery. So if you have a 0.7Vf diode, one of your ADS1115 inputs will be at about 11.3v. That is well beyond what it can safely handle. A 2:1 voltage divider would keep the voltage to less than 4v.
http://www.ohmslawcalculator.com/voltag ... calculator

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Please be positive and constructive with your questions and comments.