Vega VEGAPULS 66 enamel Operating Instructions Manual

Also see for VEGAPULS 62: Operating instructions Safety manual Quick setup guide Quick setup guide Operating instructions

Vega VEGAPULS 66 enamel Operating Instructions Manual Manual pdf 21 page image

215 Connecting to power supplyVEGAPULS 66 enamel • 4 … 20 mA/HART - four-wire31954-EN-141215suppressed, but the protective effect against high frequency interfer-ence signals remains.Warning:Considerable potential differences exist inside galvanic plants as wellas vessels with cathodic corrosion protection. Very large equalisa-tion currents can flow through the cable screen when the screenis grounded on both ends. To avoid this, the cable screen must beconnected to ground potential only on one end (inside the switch-ing cabinet) in such applications. The cable screen must not beconnected to the internal ground terminal in the sensor and the outerground terminal on the housing not to potential equalisation!Information:The metallic parts of the instrument (transmitter, process fitting, etc.)are conductively connected with the inner and outer ground terminalon the housing. This connection exists either as a direct metalliccontact or via the shielding of the special connection cable on instru-ments with external electronics. You can find specifications on the po-tential connections within the instrument in chapter "Technical data".Take note of the corresponding installation regulations for Ex applica-tions. In particular, make sure that no potential equalisation currentsflow over the cable screen. In case of grounding on both sides thiscan be achieved by the use of a capacitor or a separate potentialequalisation.With the Exd version, the minus side of the signal output is galvani-cally connected to ground via protective diodes. When connecting theinstrument to a grounded PLC, equalising currents can flow in caseof potential differences which can cause malfunctions. Make surethat there is sufficient potential equalisation from the system side orrealise the connection via switching amplifier.5.2 Connection procedureProceed as follows:1. Unscrew the housing cover2. Loosen compression nut of the cable entry gland3. Remove approx. 10 cm (4 in) of the cable mantle (current output),strip approx. 1 cm (0.4 in) insulation from the ends of the indi-vidual wires4. Insert the cable into the sensor through the cable entry5. Lift the opening levers of the terminals with a screwdriver6. Insert the wire ends into the open terminals according to the wir-ing plan7. Press down the opening levers of the terminals, you will hear theterminal spring closing8. Check the hold of the wires in the terminals by lightly pulling onthem9. Connect the screen to the internal ground terminal, connect theouter ground terminal to potential equalisationInstallation with Exapplications