255 Connecting to power supplyVEGABAR 82 • 4 … 20 mA45027-EN-170522free openings for the cable glands are therefore covered with red dustprotection caps as transport protection.Prior to setup you have to replace these protective caps with ap-proved cable glands or close the openings with suitable blind plugs.On plastic housings, the NPT cable gland or the Conduit steel tubemust be screwed into the threaded insert without grease.Max. torque for all housings, see chapter "Technical data".If screened cable is required, we recommend connecting the cablescreen on both ends to ground potential. In the sensor, the screenmust be connected directly to the internal ground terminal. Theground terminal on the outside of the housing must be connected tothe ground potential (low impedance).In Ex systems, the grounding is carried out according to the installa-tion regulations.In electroplating plants as well as plants for cathodic corrosion protec-tion it must be taken into account that significant potential differencesexist. This can lead to unacceptably high currents in the cable screenif it is grounded at both ends.Information:The metallic parts of the instrument (process fitting, sensor, concen-tric tube, etc.) are connected with the internal and external groundterminal on the housing. This connection exists either directly viathe conductive metallic parts or, in case of instruments with externalelectronics, via the screen of the special connection cable.You can find specifications on the potential connections inside theinstrument in chapter "Technical data".5.2 ConnectingThe voltage supply and signal output are connected via the spring-loaded terminals in the housing.Connection to the display and adjustment module or to the interfaceadapter is carried out via contact pins in the housing.Information:The terminal block is pluggable and can be removed from theelectronics. To do this, lift the terminal block with a small screwdriverand pull it out. When reinserting the terminal block, you should hear itsnap in.Proceed as follows:1. Unscrew the housing lid2. If a display and adjustment module is installed, remove it by turn-ing it slightly to the left.3. Loosen compression nut of the cable gland and remove blindplug4. Remove approx. 10 cm (4 in) of the cable mantle, strip approx.1 cm (0.4 in) of insulation from the ends of the individual wiresCable screening andgroundingConnection technologyConnection procedure