I'm working with linear hydraulic actuators which have multiple LVDTs (for the ram and main control valve) and I have a spec for allowed phase shift from primary to secondary for the transformers.
I'm trying to make sense of the Labview code I've been given for measuring this parameter and have found an unexplained hardcoded offset value related to this phase measurement. My analog skills are down so I feel like I'm missing something obvious.
The setup is: The excitation board is connected to the actuator via a ~25ft cable. Excitation is ~1900Hz at 5V. If I probe either near the excitation board or near the actuator, I get similar measurements for a couple of different parts that are in the 3-7 degrees range, well within the +- 10 degree spec. The problem is, the hardcoded offset is
5 degrees so some parts pass and some parts fail.I assume the cabling can impart some sort of delay thanks to capacitance/inductance of the line and perhaps this is where the offset is coming from, but I'd like to understand if this is correct and how I can characterize this to calibrate my measurement.