Emc Protection - HBK Z6FD1 Montageanleitung

5.6

EMC protection

Background information
Electrical and magnetic fields often induce interference voltages in the measuring circuit.
For reliable measurements, signal differences of less than 1μV must be transmitted with­
out interference from the transducer to the evaluation electronics.
Planning of the shielding concept
Due to the numerous application options and the different local constraints, we can only
provide you with information for correct connection. The shielding concept suitable for
your application must be planned locally by an appropriate specialist.
The load cells with shielded, round cables are EMC-tested in accordance with EC direc­
tives and identified by CE certification.
Points to be observed
S
Use shielded, low-capacitance measurement cables only (HBM cables fulfill both con­
ditions).
S
Do not route the measurement cables parallel to power lines and control circuits. If
this is not possible, protect the measurement cable with e. g. steel conduit.
S
Avoid stray fields from transformers, motors and contact switches.
S
Connect the shield of the connection cable extensively on the shielding electronics
housing. When using several load cells, connect the shield extensively to the junction
box (combination of transducer signals, e.g. type VKK2 from HBM). From there, con­
nect the measurement cable for the electronics extensively to the junction box and
extensively to the shielding electronics housing.
S
The shield of the connection cable must not be used for discharging potential differ­
ences within the system. You must therefore lay sufficiently dimensioned potential
equalization lines to compensate for possible potential differences.
Important
Potential equalization is specified for applications in potentially explosive atmospheres.
Z6
ELECTRICAL CONNECTION
11