I have load cell indicator with DB9 connector(RS-232C interface). How do I get load cell reading on my computer using Arduino.
RS-232 has a much higher operating voltage than the Arduino can handle. You'll need a go-between to interface with it, such as the Max232.
There are RS-232 shields available, as well, which are basically just breakouts for a MAX232. After that, it's just set your Serial baud rate and off you go.
You'll also need to know the syntax for your particular load cell.
If all you want to do is talk to it on your computer, just grab a USB-RS232 adapter and use a terminal program like PuTTY. I have one from TripLite.
What are you planning on doing?
I have trying to make a dyno controller and use matlab for creating GUI. GUI will have a real time, rpm vs horsepower plot and throttle control. I will get the torque reading via load cell controller(RS232) and rpm reading via hall effect sensor(using LM2907 frequency to voltage converter). And use servo to control throttle.