A system for monitoring an operation of a linear actuator-valve pair and for detecting failures at their early development stages, which comprises: (a) a linear valve for opening or closing a channel between two pipes; (b) a linear actuator for driving the valve to either a closed or an open state by fully or partially displacing a stem of the valve; (c) an angular wireless valve monitoring device for monitoring the status of the pair by inspecting an angular orientation of a main shaft, and for reporting the status to a control center; and (d) a linear to angular converter for converting the linear displacement of the stem to an angular progression of the main shaft.