Santest's Model PLR is a displacement sensor detecting the change of inductance caused by the difference of magnetic permeability. It is the linear resolver measuring the shift of relative position between rod having the cyclic change of magnetic permeability and amplifier unit containing the coil.
By adopting innovative new rod, Model PLR achieves the higher accuracy in the wider operation than conventional products. Addition to it, PLR enables 1 mico meter of resolution throughout the effective length. Phase A and B quadruple signals (90 degree phase difference / multiplied by 4) are output as the position data.
The rod of PLR consists of high magnetic permeability parts and low one which alternately put in the stainless steel pipe. The coil unit are three pairs of primary coil and secondary rolled up concentrically, which are arranged at 1/3 rod pitch length interval. Each of them applies one of three sinusoidal excitation signals at 120 degrees difference phase each others as the input signals. The inductive signals appropriate to the inputs are then induced on the secondary coils placed above each primary unit. The value of induced signals are changed according to the shift of relative position between rod and coil unit because they vary with the magnetic permeability of the rod. So then the output signal is obtained by adding three induced signals based on the addition theorem of trigonometric function. Regarding the phase change variation, it is calculated by counting the phase shift as the output signal phase change from 0 to 2pi compared with the excitation signal when the displacement changes from 0 to P.
Model PLR has (20+0.1xL) micro meter (L:stroke(mm)) linearity and its resolution is 1 micro meter. Repeatability is +- 2 micro meter. DC24V, 150mA for power supply. Operating temparature is 0 to 60 degrees (celsius). Vibration resistance is 6G, and 50G (2msec) for shock. Meet IP67.