What I am proposing is not fooling around and I am suggesting getting real measurements from TWO devices, the LVDT and an encoder that is used as the reference. The feedback devices must be connected together. Cams, springs and other linkage just confuses the issue.
| Sync an oscilloscope with the index sensor and display the LVDT on the | trace. Frequency can be inferred from measured period, amplitude read | directly, and displacement of the peak from the beginning of the trace | indicated delay. From delay and period, calculate phase.
Fine, you are taking care to make sure there is no mechanical slop. However, looking at an oscilloscope will not be enough. The input positions from the encoder and the output data positions from the resolver should be recoded so the transfer function can be determined.
After the LVDT transfer function is computed then what? Just curious. LVDTs are used for spool position feedback on hydraulic servo valves. It would be interesting to know how fast these LVDTs really are. I am curious now.
Peter Nachtwey