The refractometer system for potentially explosive atmosphere locations consists of a modified refractometer sensor PR‑21‑…‑FM, a standard indicating transmitter DTR, a sensor connector PR‑8021‑FM and a sensor cable PR‑8230‑…. The connector has to be secured mechanically by the securing clamp.
The FM‑certified sensors PR‑21‑S‑…‑FM are identified by the sensor nameplate. The indicating transmitter is a standard DTR.