Vega VEGADIS 82 Operating Instructions Manual

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Vega VEGADIS 82 Operating Instructions Manual Manual pdf 14 page image

145 Connecting to power supplyVEGADIS 82 • 4 … 20 mA46591-EN-1703285 Connecting to power supply5.1 Preparing the connectionAlways keep in mind the following safety instructions:Warning:Connect only in the complete absence of line voltage.• The electrical connection must only be carried out by trainedpersonnel authorised by the plant operator.• If overvoltage surges are expected, overvoltage arresters shouldbe installed.Power supply and current signal are carried on the same two-wirecable. The voltage supply range can differ depending on the sensor.The data for power supply are specified in chapter "Technical data".Make sure that the supply circuits are separated from the mainscircuits and of an energy-limited voltage supply, e.g. of "Class 2" (acc.to UL 1310, NEC 725 or CAN/CSA C22.2 No. 223), according to inter-nationally harmonized standard IEC 61010-1.Keep in mind the following additional factors that influence the operat-ing voltage:• Output voltage of the power supply unit can be lower under nomi-nal load (with a sensor current of 20.5 mA resp. 22 mA in case offault message)• Voltage loss on the VEGADIS 82 (see supply circuit in chapter"Technical data")You can find information on the load resistance in chapter "Technicaldata", (voltage supply of the respective sensor)The instrument is connected with standard two-wire cable withoutscreen. If electromagnetic interference is expected which is above thetest values of EN 61326-1 for industrial areas, screened cable shouldbe used.Use cable with round cross-section. To ensure the seal effect of thecable gland (IP protection rating), find out which cable outer diameterthe cable gland is suitable for. Use a cable gland fitting the cablediameter.You can find an overview of the cable glands in chapter "Technicaldata".Metric threadsIn the case of instrument housings with metric thread, the cableglands are screwed in at the factory. They are sealed with plasticplugs as transport protection.You have to remove these plugs before electrical connection.NPT threadIn the case of instrument housings with self-sealing NPT threads, it isnot possible to have the cable entries screwed in at the factory. TheSafety instructionsVoltage supplyConnection cableCable glands