This unit has an isolated internal switcher power supply. The unit will operate correctly on 12-24 VAC or 10-34 VDC. The power input is protected so power can be applied in either polarity. The supply provides the internal electronics with power totally ground isolated form the power input. No opto electronics are used so the unit is not temperature limited by the isolated supply. The power connector is a four pin plug with jack screws so the power connection can support high vibration environments. In addition to the two pins used for power input, a third pin provides access to the internal electronics ground circuit. The fourth pin provides access to an internal chassis ground that connects to internal ESD protection devices.
The package for this unit consists of a solid epoxy block. The internal electronics are assembled and tested before the encapsulation process. During the encapsulation the printed circuit board(s) are placed in a five sided box made of RTV mold parts. The cavity is filled with epoxy and the lid (top) of the mold is inserted. The curing process takes 24 hours. This type of package seals the electronics so water and contamination cannot affect the internal electronics. This type of package also provides superior resistance to shock and vibration compared to a metal or plastic box enclosure.