AD623 amplifier and Force sensor S2M

[Ngong]

Hello ,
i want to connect Force sensor S2M to a AD623 Amplifier single supply circuit in order to amplify it signal. I tried connecting Sensor to the amplifier circuit that i built on a board but i still received a mistake (a short circuit). can i have others way or some advices how i can do it successfully?
the datasheets of Sensor and Amplifier and my Circuit are attached below.
thanks.

 

[ericgibbs]

hi,
How do you have force sensor wires connected to the AD623, the Voltage source symbol in your circuit does not show any details.

E

 

[ericgibbs]

hi Ngong,
This circuit shows how your sensor should be connected to an AD623.

E.

 

[Ngong]

Thank for your feedback Ericgibbs.
the 10mV voltage at the pins 2 and 3 on the input of amplifier is considered to be the voltage that the sensor can suppose to give out.Its only an example.
the circuit posted ist what i used to connect the sensor. Removing the input voltage, i connected both gray - Black and blue-green respectly to -/+ supply voltage (here 8V for example). That means to pins 4 and 7. White and red cable are been connected at the input of amplifier(white to pin 3 and red to pin 2). Thats what i done. But i did'nt work.
I hope its what you mean.
Thank.

 

[ericgibbs]

hi,
From your description you have connected it correctly according to the datasheet for the Sensor and it should work.??

Without a load on the sensor , what does the AD623 output read on a voltmeter, also does the reading change if you load the sensor.??

Does your simulation work as shown in the circuit diagram you posted.??

 

[ericgibbs]

hi,
This is a simulation of Sensor at 0mV to 10mV.

 

[Ngong]

Hi. Ericgibbs sorry i did a mistake by posting the circuit. below is the right Circuit i simulated and it worked.
the Amplificationsfactor is 100. For example als result i received by input: 4.131mV at the output von amplifier u= 417.409mV. This result is without the sensor By connecting the sensor such as described. I did'nt work.

 

[Ngong]

Hi, thank you very must for your support Ericgibbs. your circuit will helps me certainly for the next step. But i have some question about your circuit for the understanding.
Why did you added R1,R2 and C1 at the output of Pins 2 of 3 of Amplifier?
Thanks !

 

[ericgibbs]

Hi,
I would suggest that you power the Sensor with 8V as shown in your circuit, do not connect the White and Red leads.

You should be able to measure 4V on the RED wire to 0Volts, also measure 4V on the WHITE wire.

Measuring , using a sensitive voltmeter, between RED and WHITE it should be very close to 0V, then load the sensor and the WHITE wire should go a few milliVolts positive with respect to the RED wire.

The above test should check the Sensor, tell me what the voltage measurements indicate.

 

[Ngong]

Im out from the lab. I will try to answer you question tomorrow. concerning your cuircuit that you have posted, i will also to built it on the board an testing what it done.
I really send you all my thanks for your support Ericgibbs.
Thanks.

 

[Ngong]

Hi Ericgibbs, another question, where is the pin 4 in the circuit you have posted.
thanks.

 

[Ngong]

It is the ground?

thanks

 

[ericgibbs]

It is the ground?

thanks

hi,
Pin4 is 0V [the ground triangle symbol] and Pin7 is +V8.

EDIT:
You can make a very simple circuit to check the AD623, see image.

 

[Ngong]

Thank for the reply,the your circuit help me to understand what i wanted.
The circuit i posted worked too. the mistake haved by connecting came from the way i use th voltage. I must use an unipolar system whithout ground.
All wire supposed going to ground were connected to (-) that mean 0V. the problem is now solved. I'm able going forward with the project.
I send you all my thank for the support. It was very kind.
Thank you Ericgiggs

 

[ericgibbs]

Thank for the reply,the your circuit help me to understand what i wanted.
The circuit i posted worked too. the mistake haved by connecting came from the way i use th voltage. I must use an unipolar system whithout ground.
All wire supposed going to ground were connected to (-) that mean 0V. the problem is now solved. I'm able going forward with the project.
I send you all my thank for the support. It was very kind.
Thank you Ericgiggs

hi,
Thanks for letting me know its working OK, I hope the project is successful.
E

 

[Ngong]

The next step is to braze the circuit on a Board. The Lab-prof is satistfied with the circuit.The block circuit will be brazed on a board and at the output of amplifier i will built a lowpass that will be connected at the input of a DAQ(Data acquisition) system.
I have a question. Ist the choise of value of Resistance and capacitor for building the lowpass necessary. According for the DAQ-system. I use a NI-DAQmx.
Thanks.

 

[ericgibbs]

The next step is to braze the circuit on a Board. The Lab-prof is satistfied with the circuit.The block circuit will be brazed on a board and at the output of amplifier i will built a lowpass that will be connected at the input of a DAQ(Data acquisition) system.
I have a question. Ist the choise of value of Resistance and capacitor for building the lowpass necessary. According for the DAQ-system. I use a NI-DAQmx.
Thanks.

hi,
What cut off frequency do you require for the LPF .??

I guess you have this link already.???
https://digital.ni.com/public.nsf/allkb/1C60EDAB0E3AAA5F86256D24006BFA68

BTW: the word 'braze/d' is 'solder/ed' in translation.

 

[Ngong]

Thank for the link. I will try to read carefully for knowing what i need or have to do.
Good day Ericgibbs.

Thanks.

 

[Ngong]

Hi Ericgibbs, how about your day? i hope good.
please i have a question about the last topic. Below it is the circuit i used for the communication between sensor an Amplifier. It works normally well without that i connect the pin 5 (reference supply) at the ground 0V). By connecting i receive no reaction of force sensor. Are you have an idea about that?
what effect have the reference Supply in a type of circuit?

Thank.

 

[ericgibbs]

hi,
The first check would be the polarity of the bridge [ sensor] output wires, if they are the wrong way around, when you apply a force to the sensor it would 'try' to drive the AD623 output below 0V.
As its a single supply to the AD623, the output will appear to limit at zero volts [ when the Vref pin#5 is connected to 0V.]

So reverse the input wires from the sensor to the AD623 input and retest.
E.

EDIT:
Also you have an error on the circuit diagram, see my changes.