VEGAPULS WL 61 - 4 … 20 mA/HART - two-wire

5 Connecting to power supply5 Connecting to power supplySafety instructionsVoltage supplyConnection cable5.1 Preparing the connectionAlways keep in mind the following safety instructions:•Connect only in the complete absence of line voltageIf overvoltage surges are expected, overvoltage arresters shouldbe installedPower supply and current signal are carried on the same two-wirecable. The voltage supply range can differ depending on the instrumentversion.The data for power supply are specified in chapter "Technical data".Provide a reliable separation between the supply circuit and themains circuits according to DIN VDE 0106 part 101.Keep in mind the following additional factors that influence the operatingvoltage:• Output voltage of the power supply unit can be lower under nominalload (with a sensor current of 20.5 mA or 22 mA in case of faultmessage)•Influence of additional instruments in the circuit (see load values inchapter "Technical data")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.For instruments with housing and cable gland, use cable with roundcross-section. A cable outer diameter of 5 … 9 mm (0.2 … 0.35 in)ensures the seal effect of the cable gland. If you are using cable witha different diameter, exchange the seal or use a suitable cable gland.We generally recommend the use of screened cable for HART multidropmode.5.2 Wiring planWire assignment, connectioncable1238061-EN-121011VEGAPULS WL 61 • 4 … 20 mA/HART - two-wireFig. 23: Wire assignment fix-connected connection cable1 brown (+) and blue (-) to power supply or to the processing system2 Shielding5.3 Switch-on phaseAfter connecting the instrument to power supply or after a voltagerecurrence, the instrument carries out a self-check for approx. 30 s:23