KROHNE OPTISONIC 7300 EN - Manual (Page 37)

ELECTRICAL CONNECTIONS
4
37
OPTISONIC 7300
www.krohne.com 09/2012 - 4001102303 - MA OPTISONIC 7300 R03 en
4.7.2 Description of the electrical symbols
mA meter
0...20 mA or 4...20 mA and other
R
L
is the internal resistance of the measuring point including the cable
resistance
DC voltage source (U
ext
), external power supply, any connection polarity
DC voltage source (U
ext
), observe connection polarity according to
connection diagrams
Internal DC voltage source
Controlled internal power source in the device
Electronic or electromagnetic counter
At frequencies above 100 Hz, shielded cables must be used to connect the
counters.
R
i
Internal resistance of the counter
Button, NO contact or similar
Table 4-1: Description of symbols