Strain gauge scaling/calibration

I'm relatively new to working with plc's and I need some help.

We need to run a fatigue test on a length of pipe and it will be controlled by input from a strain gauge. We're going to flex the pipe up and down and measure longitudinal strain.

The strain gauge will be conditioned to a 4-20mA signal into our plc's analog input card. My idea for scaling was to set my low cal value being zero force on the pipe and, using a dial indicator located near the strain gauge, flex the pipe a known distance and use that as my high cal value. The dial indicator is traceable. Would this then give me traceable strain values? Thanks for any input.

That sounds like a reasonable plan. Your high-cal value should be the reading at the maximum possible bend distance. I suppose that as the pipe metal starts to break, then the strain level at the max bend will gradually decrease, and hit 0 after it breaks completely. It probably will depend on whether your bending machine has travel limit stops, or moves the bend point farther as the metal weakens.

The strain values will not be traceable, becuse you compare a distance with a force, however when you use a weight it will be traceable, as a weight is a force to ground.
and look at lanc for the setup

I dont know if this helps or not, but I have used Strain Gage amplifiers and Load Cells on each of my machines Ive done the last few months. What I ended up using was a SCP (Scale with Parameters) this allowed me to select what I wanted my output range to be equal to based on what the input range was. It works fairly well and is accurate. If you need some more info let me know.