# 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
622
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
622

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,
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
622

Last edited:

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