System Manual Compact Systems 7 Start-Up
HI 800 141 E Rev. 2.02 Page 45 of 110
7.1.1.3 Natural Convection
When the natural convection is used, the lost heat is dissipated through the enclosure walls.
Requirement: The ambient temperature must be lower that the temperature within the
enclosure.
The maximum temperature increase (T)
max
of all electronic devices within the enclosure is
calculated as follows:
P
V
(
T)
max
= ———
k • A
The power dissipation P
V
can be calculated based on the specifications for the electric power
rating of the system and its inputs and outputs.
Example: Calculation of power dissipation P
V
for the F35 controller
Idle current consumption of the controller: 0.75 A at 24 V.
8 digital outputs with current consumption of 1 A each at 2 V.
The current consumption of the digital, analog and counter inputs can be neglected.
As a result, the maximum thermal power dissipation is approx. 34 W.
The temperature within an enclosure can also be calculated in accordance with VDE 0660, Part
507 (HD 528 S2).
All considerations about heat must take every component within a cabinet or enclosure into
account!
7.2 Installation and Mounting
The safety-related HIMatrix controller systems can be installed on mounting surfaces, and also
in closed enclosures such as control stations, terminal boxes and control cabinets. They have
been developed in compliance with the relevant standards for EMC, climate and environmental
requirements.
The list of the standards that must be observed is specified in Chapter 2.2 and in the manuals
for the HIMatrix systems.
The protection class of the HIMatrix systems (IP20) can be increased by installing them in an
appropriate enclosure in accordance with the requirements. In doing so, appropriate heat
dissipation must be ensured (see Chapter 7.1).
The HIMatrix compact systems are mounted on a 35 mm DIN rail and not directly on a base.
Only personnel with knowledge of ESD protective measures may modify or extend the system
wiring.
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