OBJECTIVE
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The following image shows, within the OpenTherm page of the RegConfig, the position of the Heating Cascade Algorithm Control section and the Secondary Heating Temperature Compensation section, closely related to the PID cascade algorithm:PHOTO TBD
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The cascade algorithm can be of three types:
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Attenzione: non utilizzare G0 in quanto è il generatore OpenTherm utilizzato con il prodotto DOT, non con il sistema REG, quindi nella logica di cascata non viene mai considerato.
Warning
Do not use G0 as it is the OpenTherm generator used with the DOT product, not with the REG system, therefore it is never considerate in the cascade logic.
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However, it is important to underline that “PID Cascade” and “Buffer Tank Compensation Temperature” are two different and separate functions, which can operate together or separately (e.g., the “Buffer Tank Compensation Temperature” can be also used for other types of cascade algorithms, and also for Parallel functioning), which incidentally “share” the same sensor, as the requirement for both algorithms is to monitor the “final” temperature provided by the group of generators.
Note
The “Buffer Tank Compensation Temperature” is not the subject of this technical part, which instead focuses on the “PID Cascade”.
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so, if we consider a delta T of 4 K and a delay T of 5 minutes before switching on a second generator, then the value of Pid I to be entered is 87 (1740 / 4 * 5). The lower the Pid I parameter, the more time will pass before an additional generator is added.
Note
The values 160 and 1740 were derived from formulas implemented for this specific algorithm!
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The lower part of the OpenTherm page shows for each generator the result of the heating/cooling and DHW requests (red box) and the feedback from the generators to the REG System (yellow):
PHOTO TBD
Highlighted in red you have:
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