PC104

This PC104 compliant stackthrough module offers (1) three-wire transformer isolated "PROGRAMMABLE" LVDT/RVDT outputs with wrap-around self test and optional excitation supply.

Instead of buying cards that are set for specific outputs, the uniqueness of this design makes PC104 possible to buy our generic card that PC104 can be programmed and reprogrammed in the field for any excitation and signal voltage between 2.0 and 28 volts. One transformer isolated excitation is supplied for the A, B output pair. User selects the desired A+B voltage. After PC104 is done, the card will automatically set the correct B voltage for any programmed A voltage. Use of a ratiometric design eliminates errors caused by excitation voltage variations. The outputs are stable with temperature and switching spikes are not noticeable. To simplify logistics, Part number, S/N, Date code, & Rev. are located in permanent memory locations.

Automatic background bit testing where the output of each channel of PC104 is compared against the commanded input to a testing accuracy of 0.1% FS and each Signal and Excitation is monitored. Any failure triggers a flag. The testing of PC104 is totally transparent to the user, requires no external programming, has no effect on the standard operation of this card and can be enabled or disabled via the bus. The results of PC104 are available in status registers. Principal of Operation (LVDT): Typically the primary is excited by an ac source, causing a magnetic flux to be generated within the transducer. Voltages are induced in the two secondaries, with the magnitude varying with the position of the core. Usually, the secondaries of PC104 are connected in series opposition, causing a net output voltage of zero when the core is at the electrical center. When the core is displaced in either direction from center the voltage increases linearly either in phase or out of phase with the excitation depending on the direction.