Steel coil is lifted up by hydraulic cylinder. I need to measure weight of the steel coil from the hydraulic pressure when lifted up. Could anybody give some suggestion how to calculate weight from the hydraulic Pressure.
Weight ought to equal the area of the piston times the pressure to lift.
in other words 100 psi working on a 1 square inch piston ought to lift 100 pounds straight up. If linkage/levers are involved it gets more complicated as the mechanical advantage changes with the geometry. But it should be proportional, picking up a ton should take half the pressure of picking up two tons. This all ignores tare, seal drag, etc. But you get the idea.
Depends how accurate you require to weigh, if for weights and measures, fit load cell and print out ( calibrated.)
If you can live with cylinder / system mechanical losses, Fit a pressure gauge in LIFT side of cylinder and calibrate against known weights, (recalibrate at regular intervals). you can calculate the lift force (weight) but this will be approximate as you do not know losses, / mechanical efficiency of system.