PiXtend V2 -L- Hardware Manual
6.2.1.Thermal consideration
The PiXtend V2 hardware (without Raspberry Pi computer) has been designed for use in
industrial environments and is designed for ambient temperatures from 0 °C to 55 °C -
without restrictions.
The Raspberry Pi computer has not been specifically designed for the industry but can be
used for many applications in this environment. An important point is the ambient
temperature at which the computer is used.
We have carried out detailed climate tests and developed appropriate application
scenarios, the results of which are presented below.
General information about Raspberry Pi & CODESYS
The Raspberry Pi 3 B & 3 B+ computer has an application processor with four processor
cores (ARM Cortex-A53). The chip also includes a graphics processor with two cores
(Broadcom Dual Core VideoCore IV).
If all of the cores are 100 % loaded, the internal temperature of the chip reaches its
maximum temperature (85 °C) at room temperature (25 °C) and prevents further heating
by means of built-in mechanisms - the computing power is limited.
However, the above-mentioned load case of 100 % on all cores is not realistic or is not a
practical application of a computer-based control.
From our experience with linux-based CODESYS controls, we can find the following:
- CODESYS V3 (as of May 2018) always uses only one processor core and is therefore
loaded. There is currently no multi-core support.
→ the thermal load from the control application is reduced to one processor core
- The total load on the processor core running the CODESYS runtime should not exceed
80 %. If, for example, the processor is loaded with 90/95 %, the system as a whole
becomes unstable. Tasks are not processed at the desired time anymore and under
certain circumstances low-priority tasks are no longer executed.
→ Regardless of the ambient temperature and the specific device, the CPU utilization of a
computer-based controller should not be over 80 %.
- The graphics processors are not loaded, even when using the CODESYS web
visualization directly on the device.
With these findings, we defined the following application:
www.pixtend.com
Copyright by Qube Solutions GmbH
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