voltage to force translation ?

[jani12]

A transducer or sensor is connected to Force measurement unit. When force is applied to sensor, Sensor Developments Inc. PMAC 2000 Force measurement unit displays the Force in Newtons.

On back of PMAC 2000 unit, there is 9-pin I/O Connector. Please find description of this connector attached. My interest is Analog Output pins from this connector. I need to connect these Analog Output Pins to my Microcontroller based embedded application. My target Microcontroller A/D is 10-bit and A/D Reference Voltage is 5V.

Please check my connection as follows:

AOUT - (Pin 4) connects to unused Analog Pin in my microcontroller.
AOUT + (Pin 2) connects to different unused Analog Pin in my microcontroller.

Do I need to connect GND (Pin 3) to Ground on my target board ?

My understanding is that sum of AOUT+ and AOUT- is 5V. In my embedded software, how should I calculate voltage, should I simply subtract AOUT- from AOUT+ ?
What is the translation of voltage to force in Newtons ? What voltage is what amount of force ?

The attached description says AOUT+ is driven positive or negative with respect to AOUT- . Please provide examples of some AOUT+ and
AOUT- voltages I will see on my Microcontroller Analog Inputs ? I don't think I can have negative voltages going into my Analog Pins on my Microcontroller because A/D reference voltage in my microcontroller is 5V. So, I believe Analog Input values going into my
microcontroller need to be 0V to 5V. If yes, how do I know PMAC 2000 will send Analog Voltages in between 0 to 5V ?

Please explain following:
"The Output impedance of each is 620 ohms and the output voltage is +1.0V nominal for 2mV/V full scale sensor.
What is 2mV/V ? Is this a typo ?

 

[JimB]

for 2mV/V full scale sensor.
What is 2mV/V ? Is this a typo ?

Many sensors need a supply, an excitation voltage.
A sensor with an output of 2mV/V, when set to full scale, would give 2mV output for each volt of excitation.

For example, say the excitation voltage was 10volts, then at full scale the output of the sensor would be 20mV.

JimB

 

[cowboybob]

My understanding is that sum of AOUT+ and AOUT- is 5V. In my embedded software, how should I calculate voltage, should I simply subtract AOUT- from AOUT+ ?
What is the translation of voltage to force in Newtons ? What voltage is what amount of force ?

Is the RS232 output of the instrument inadequate or inappropriate for your needs?

 

[Ian Rogers]

What is the translation of voltage to force in Newtons ? What voltage is what amount of force ?

The output of the sensor ( As Jim so beautifully put) is in the order of mV... The transducer / sensor will have a full scale output reference... ie our load cells are rated ... 1te, 2te, 5te and 10te...... That means if they were 2mV/V ( 2 milli volt per volt ) when the output was 20mV/V there would be a force of 1te on the 1te cell.... 10mV would represent 0.5te and so on..

Our load cells are not linear ( not many are ) so the force / voltage are only correct at 0mV and 20mV...

 

[jani12]

>> Is the RS232 output of the instrument inadequate or inappropriate for your needs?
It doesn't have Analog Output.