Vega VEGACAL 62 Operating Instructions Manual - page 15
15
5 Connecting to power supply
VEGACAL 62 • For connection to a signal conditioning instrument
30317-EN-170503
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
•
Connect only in the complete absence of line voltage
•
If overvoltage surges are expected, overvoltage arresters should
be installed
Tip:
We recommend using VEGA overvoltage arresters B63-48 and
ÜSB 62-36G.X.
Inhazardousareasyoumusttakenoteoftherespectiveregulations,
conformityandtypeapprovalcertificatesofthesensorsandpower
supply units.
Power supply and current signal are carried on the same two-wire
cable.Thevoltagesupplyrangecandifferdependingontheinstru-
ment version.
Thedataforpowersupplyarespecifiedinchapter"Technical data".
Provide a reliable separation between the supply circuit and the
mains circuits according to DIN VDE 0106 part 101. The VEGA power
supply units VEGATRENN 149AEx, VEGASTAB 690, VEGADIS 371
as well as all VEGAMETs meet this requirement.
Keepinmindthefollowingadditionalinfluencesontheoperating
voltage:
•
Output voltage of the power supply unit can be lower under nomi-
nal load (with a sensor current of 20.5 mA or 22 mA in case of fault
message)
•
Influenceofadditionalinstrumentsinthecircuit(seeloadvaluesin
chapter"Technical data")
The instrument is connected with standard two-wire cable without
screen. If electromagnetic interference is expected which is above the
test values of EN 61326 for industrial areas, screened cable should
be used.
Make sure that the cable used has the required temperature resist-
anceandfiresafetyformax.occurringambienttemperature
Use cable with round cross-section. A cable outer diameter of
5…9mm(0.2…0.35in)ensuresthesealeffectofthecablegland.
Ifyouareusingcablewithadifferentdiameterorcross-section,
exchange the seal or use a suitable cable gland.
If screened cable is required, connect the cable screen on both ends
to ground potential. In the sensor, the screen must be connected
directly to the internal ground terminal. The ground terminal on the
outside of the housing must be connected to the potential equalisa-
tion (low impedance).
Note safety instructions
Take note of safety
instructions for Ex
applications
Voltage supply
Connection cable
Cable screening and
grounding