Wiring the block terminal - SCXI 1314.

[qwerty240576]

Dear all,

I am trying to acquire a deformation signal from a steel bar. I have actually two identical steel bars and I have installed a strain gauge (SG) on each sample.
My aim was to set up the configuration named: quarter bridge II (SCXI-1520 - ser Manual).
Looking at the scheme you can see at page 2-3, I still have some doubts on how to wire the Wheastione Bridge.

Each SG has got three wires (red, black and white). Following the above-mentioned NI scheme, I did what follows:

1) red    wire of SG-R4 ----> P+;
2) black wire of SG-R4 ----> S+;
3) white wire of SG-R4 ----> SCA #1;
4) red    wire of SG-R3 ----> SCA #1;
5) black wire of SG-R3 ----> P-;
6) white wire of SG-R3 ----> SCA.

Is it correct? If it is so, I have to say that this was just on of the possible solution I could guess!
Hence, might you please give me some simple rules to read schemes like those ones?

Thanx in adavance,

qwerty

[qwerty240576]

Mmmh.. I am re-reading what I wrote down. I did some mistakes...
The connections I did are:


1) red    wire of SG-R4 ----> P+;
2) black wire of SG-R4 ----> S+;
3) white wire of SG-R4 ----> SCA #1;
4) red    wire of SG-R3 ----> S+;
5) black wire of SG-R3 ----> P-;
6) white wire of SG-R3 ----> SCA #2.

I'm sorry for teh wrong post. Is the shunt resistor properly set-up?

I cannot have a measurement by a quarter bridge conf. I, because I've just 350 ohm resistors in the terminal block. Anyway, when I try to warm both sample simulateneously (by using a hairdryer), the wheastone bridge in a rush starts sensing the temperature rising and the deformation varies a lot (hundred of microstrains in 20 seconds, while I am warming both sample by a common hair-dryer 40 centimeters apart).
Is this a common behaviour? Is still the bringe compensated for temperature effects or...?

Thanx in advance,

qwerty

[Logan_081]

Hi qwerty

What about your third wire? Could you update your post by adding the sensor's datasheet?

regards

[qwerty240576]

In the pdf attached, one can see a view of the connections I did.
Thanx in advance,
qwerty

[Logan_081]

Hi,

I suppose you perform a correct way to connect the sensor's wires to the SCXI 1314 terminal block. Anyway i suggest you to check the Connection Diagram Tab in your MAX.

regards