VEGA VEGASON 51K…53K - Manual (Page 36)

36 VEGASON 51K … 53K
Electrical connection
5 Electrical connection
5.1 Connection and connection
cable
Safety information
Ensure that the instrument is unpressurised
before you start work. Always switch off the
power supply before you carry out clamping
work on the ultrasonic sensors. Protect your-
self and the instruments, especially when
using sensors which do not operarate with
low voltage.
Skilled staff
Instruments which are not operated with
protective low voltage or DC voltage must
only be connected by skilled staff.
Connection
A standard two or four-wire cable (sensors
with separate supply) with max. 2,5 mm
2 can
be used as connection. Very often the "elec-
tromagnetic pollution“ by electronic actuators,
energy lines and transmitting stations is so
considerable that the two-wire line or four-
wire line should be screened.
We recommend the use of screening. This
screening prevents future interferences. Only
earth the cable screens on both ends (on the
sensor and on the processing system) when
you have determined, by measurement, that
no or only lowest earth compensating cur-
rents flow via the screens. Use a very low
impedance earth connection (foundation,
plate or mains earth).
Ex-protection
If an instrument is used in hazardous areas,
the necessary regulations, conformity and
type approvals for systems in Ex-areas must
be noted (e.g. DIN 0165).
Intrinsically safe circuits with more than one
active instrument (instrument delivering
electrical energy) must not be connected.
Please note the special installation conditions
(DIN 0165).
Connection cable
Note that the connection cables are specified
for the expected operating temperatures in
your systems. The cable must have an outer
diameter of 5 … 9 mm to ensure the seal effect
of the cable entry. Cables for intrinsically safe
circuits must be marked blue and must not be
used for other circuits.
Earth conductor terminal
On VEGASON 51/52 sensors the earth con-
ductor terminal is galvanically isolated. The
sensors are shockproof. On the VEGASON
53 sensor the earth conductor terminal is
galvanically connected to the metal trans-
ducer diaphragm.