I am using NI 9237 and RJ50 conector to acquire a signal from a load cel.
From data sheet, it recommends me to plug the 4 wires that come from load cell in holes number 2 and 3 for excitation and 6 and 7 for acquisition. But still with high levels of noise. I read in data sheet there is an alternative conection but with 6 wires (figure attached). I didnt understand how to connect it because from my load cell only comes up 4 wires instead of 6. Any one can help me ?
Thanks a lot,
consult first your load cell's manual, this will tell you, what the pinout of your sensor is. Generally, the sensor will need an excitation of 2.5V or 3.3V or 5V. The output signal should be in the order of few Millivolts. Also check this link from NI:
Also, the manufacturer of the load cell should state, what the two factors of converting from mV to Nm (or N) are. NI-9237 will return you a raw signal, but you have to apply a multiplication and addition in order to get your load value in Labview.
Hi Lysandros, thanks for your answare.
My load cell manual says 2mV/V whith excitation from 10 to 15 V.
I have already calibrated it to convert mV answares to N. I have already alson seen the link you recommended me. The point is that i dont understand how can i make a different connection with 6 wires if from my load cell only comes 4 wires.
Sorry, and thanks again,
If your load cell has 4 wires, then they are probably
Excitation +, Exicitation -, Analog Output +, Analog Output - ? If this is the case, you do not have a "Sens" option (which is used, in order to control, what the actual local excitation value is, i.e. if it has droped due to cabling resistance etc), then you do not need a 6 wire connection. Just connect the four load cell wires to the corresponding NI-9237 pins.