FI002K0018v1530hUK – THS/21 Instruction manual for installation, use and maintenance
5
MAINTENANCE
ORIGINAL
INSTRUCTION 185
5.5 Electromagnetic compatibility verification of the installation environment
The CEIA Metal Detector has a high immunity against electromagnetic interferences.
However the installation environment can have electrical and/or mechanical noise sources that
produce a residual signal, visible on the Metal Detector display without product in transit, which can
lead to false alarms during the normal operations with the product in transit.
In this case it is necessary to locate the possible noise source and to perform the proper corrective
actions. A distinction is made:
-
Electrical
Noise
. Generated by electromagnetic sources out of the Metal Detector itself, can
be conducted through the power cables and/or the connection with other devices or radiated
through the same cables or from electromagnetic sources (including possibly adjacent Metal
Detectors) in the nearby of the Metal Detector Probe. Disabling temporarily the Metal Detector
transmission (TX=OFF), the contributions of this type of noise remain always visible in the
bargraph.
-
Mechanical noise
. Caused by the presence, near the probe opening, of fixed or moving metal
masses (see also minimum respect distances) or intermittent loops
1
(rings).
Disabling temporarily the Metal Detector transmission (TX=OFF), the contributions of this type
of noise are not visible anymore in the bargraph.
If the noise is not immediately identifiable, the Metal Detector has some procedures to be performed
with the operative detection settings and without the product in transit, whose results give a
qualitative measure of the noise and can provide information about possible sources.
The described verifications give qualitative indications about the installation environment compatibility.
It is however necessary, after the corrective actions, to verify the correct operative functioning of the Metal Detector with
the product in transit, in the normal operative conditions.
Before performing the verifications, check that the noise is not due to a nearby Metal Detector; in such case simply
synchronize the two Metal Detectors through the selection of different transmission channels (see
Configuration
menu).
1
The presence of contacts between metal parts can determine the formation of one or more conductive ring paths,
along the bearing structure or others adjacent to the Probe; in case these contacts are accidental or made through
discontinuous junctions (due to vibrations, bending of the structure or variations in the electrical characteristics of the
joints themselves), these could cause an interference signal for the Probe itself, the greater the more the surface of the
created loop is large and close to the Probe opening. Possible causes: rollers or crossbars screwed on the conveyor
belt; intentional contacts between metal parts or accidental (i.e. broken or corroded welds).
