General Remarks Regarding The Ce Marking; Data Connections; Signal Connections - Rohde & Schwarz HAMEG HM8123 Benutzerhandbuch

General information concerning the CE marking

General remarks regarding the CE marking

HAMEG measuring instruments comply with the EMI
norms. Our tests for conformity are based upon the rele-
vant norms. Whenever different maximum limits are
optional Hameg will select the most stringent ones. As
regards emissions class 1B limits for small business will be
applied. As regards susceptibility the limits for industrial
environments will be applied. All connecting cables will
influ-ence emissions as well as susceptability considerably.
The cables used will differ substantially depending on the
ap-plication. During practical operation the following
guide-lines should be absolutely observed in order to
minimize emi:

1. Data connections

Measuring instruments may only be connected to external
associated equipment (printers, computers etc.) by using
well shielded cables. Unless shorter lengths are prescri-
bed a maximum length of 3 m must not be exceeded
for all data interconnections (input, output, signals, con-
trol). In case an instrument interface would allow connec-
ting several cables only one may be connected. In general,
data connections should be made using double-shielded
cables. For IEEE-bus purposes the double screened cable
HZ72 is suitable.

2. Signal connections

In general, all connections between a measuring instru-
ment and the device under test should be made as short
as possible. Unless a shorter length is prescribed a ma-
ximum length of 3 m must not be exceeded, also, such
connections must not leave the premises. All signal con-
nections must be shielded (e.g. coax such as RG58/U).
With signal generators double-shielded cables are man-
datory. It is especially important to establish good ground
connections.
3. External influences
In the vicinity of strong magnetic or/and electric fields even
a careful measuring set-up may not be sufficient to gu-
ard against the intrusion of undesired signals. This will not
cause destruction or malfunction of Hameg instruments,
however, small deviations from the guaranteed specifica-
tions may occur under such conditions.
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