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Restriction of the switching power
Due to the different physical properties of heat emitters, restrictions can be imposed on their
permissible switching capacity depending on the type of heat emitter.
Short-wave halogen or infrared emitters ("flash emitters") have a high starting current due to
their relatively low cold resistance. The starting current can be several times the rated
current, especially during the first half waves.
Overloading of the internal fuses of the POM can occur depending on the number of
switching operations as well as the duration of switching operations and pause times.
NOTICE
Restriction of the switching power
The power limit for each POM is set by the technical parameter "Current carrying capacity
per output, max. for heating elements with high inrush current"
(see Technical specifications (Page 163)) for each POM.
Therefore, we recommend you to have Siemens AG measure radiation sources with a high
inrush current
In this regard, read the information about using Category AC 3 contactors (see
Connecting the three-phase line supply (Page 57)).
Selection of the incoming fuse for POM4320 Highend
Depending on the selected connection type, an incoming fuse is also required for the
POM4320 Highend. This fuse must only meet the requirements for line protection. This
means that gG fuses of size 14x51 can be used. The nominal value of the current depends
on the connected load.
Recommended fuses: e.g. Siemens SENTRON, cylindrical fuse-link, 14x51 mm, 3NW61
If you connect channels in parallel, only one fuse is possible up to a current of 50 A. You
must use 2 identical fuses for higher values. For UL applications, use the same fuses as for
fusing the outgoing line.
Derating of fuses
Note that fuses are subject to derating at high ambient temperatures, i.e. the rated current
for a fuse is reduced.
SIPLUS HCS4300 PROFINET/PROFIBUS DP
Operating Instructions, 10/2019, A5E35452705A/005
Application planning
4.4 Installation location
33
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