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# How to connect this strain gauge?

#### kusspuss

Aug 25, 2023
32
Do a simple test, no arduino, just module and a small V into module inputs :

View attachment 60480

Replace above probe with your module inputs, and set its G to 10, and use
the diamond tool to predict, for the Vref you have, what output should be,
and compare that with what the test gives you.

The V above is ~ 122 mV. Note the CM V is ~ 2.5V

Regards, Dana.
yes i am trying to do it , i have one confusion that how can i set G=10 for Ad620 Module

Feb 19, 2021
827
You are reading the datasheet right ?

From the datasheet, or use the tool :

Or use the tool :

Regards, Dana.

Last edited:

#### kusspuss

Aug 25, 2023
32
You are reading the datasheet right ?

From the datasheet, or use the tool :

View attachment 60482
Or use the tool :

View attachment 60483

Regards, Dana.
i have successfully tested DMM by paste one linear strain guage at beam, some assumptions has been made however the DMM is good, i am doubt for my strain gauge there is something wrong in my circuit.

i belive this strain guage that i have posted not.getting any current or may be strain gauge below some cut connections , so confused

attached video

Attached Video DMM

please need your guide to make succefully circuit for this strain gauge as discussed before , thank you very much for your precious time

#### Attachments

• SG1.jpg
64.8 KB · Views: 0

#### kusspuss

Aug 25, 2023
32
You are reading the datasheet right ?

From the datasheet, or use the tool :

View attachment 60482
Or use the tool :

View attachment 60483

Regards, Dana.
thank you , in circuit given below as i calculate that

Gain = 1 + (49.4kΩ / Rg)
Rg = 49.4kΩ / (Gain - 1)
Rg = 49.4kΩ / (10 - 1)
Rg = 49.4kΩ / 9

Rg ≈ 5.49kΩ
so Rg is 5.49

#### Attachments

• circuit.png
560.3 KB · Views: 1

Feb 19, 2021
827

Notice how the Vref pin sets Vref to 2.5V and bottom of its
10K divider R is returned thru ground. Same ground as -
supply of strain gauge ? Ignore the G R value in above pic.

Excite - in above pic grounded. Excite + to +5 thru a 120 ohm R
as discussed in #54 post.

Also to get range out 0 - 5 you need 9V on AD620 +, and <= -2
V on its ground pin. If you dont care, for the purposes of testing,
connect AD620 pin to ground and just observe AD620 output.
But Keep in mind its output will not swing to ground, unless its
ground pin is at least 2 volts below ground. Lastly to get the
0 - 5V for +/- 100 mV in from strain gauge you need G set to 25.

Regards, Dana.

Last edited:

Feb 19, 2021
827

Last edited:

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