OBJECTIVE
This technical information details the new Power Cascade algorithm that can be selected within the OpenTherm page of the RegConfig Configurator.
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The following image shows, within the OpenTherm page of the RegConfig, the position of the System Cascade control Algorithm section (redblue) and the Buffer tank Compensation Temperature section (blue), closely related to the PID cascade algorithmyellow):PHOTO TBD
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The cascade algorithm can be of three types:
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Enabled OpenTherm generators are those generators that have a number (which can range from 1, highest priority, to 8, lowest priority) in the Generators section (highlighted in green) on the OpenTherm page and not OFF in the box corresponding to the “Heat/Cool” column. The number indicates the priority of the call, so in the image below G1 and G3 generators have priority 1 (they are called first), while G2 has priority 2 and G4 priority 3:
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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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The result of the settings made is displayed at the top right of the OpenTherm “Generator Demand Status” page:PHOTO TBD
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Enable/set Heating: if the square is ticked, this means that there is a request to the generators and in the rectangle on the right is indicated the required set point. For heat pumps, the set point is either heating or cooling. If the square is not ticked and the set point is zero, this means that no demand is coming from the circuits to OpenTherm.
Enable/Set DHW: if the square is ticked, this means there is a request to the generators and in the rectangle on the right is indicated the required set point for the production of Domestic Hot Water. If the square is not ticked and the set point is zero, this means that no demand is coming from the circuits or the DHW page to OpenTherm.
N. active generators (cascade): indicate how many generators have been activated for the cascade in heating or cooling (not for DHW production).
The last rectangle at the bottom (yellow box) is the countdown of the Stop between changes in hundredths of a second.
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The request for H = Heating, W = DHW;
The required temperature in heating [°C];
The heating power [%] is the upper limit and it is the greater between Idle and the lower of the active boiler power plus the Gap.
Warning
If the generator is used for DHW production only, both the required temperature and the power are at zero, the values that are passed in case of DHW production are those that are displayed in Generator Demand Status (top right of OpenTherm page).
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Water outlet temperature (T outlet), Water inlet Temperature (T inlet), DHW Temperature [°C]: are the readings of the generator sensors if present.
Pow.: power delivered by the generator in % (refer to boiler manufacturer’s manual).
OT error: most frequent OpenTherm error (Ts = service request, Rr = remote reset enabled, Lp = low water pressure, etc.).
OEM Error: indication of the number of the error, refer to generator manual for diagnostic.
Reset: reset of the error, it only works if the boiler manages it; refer to the generator manual for diagnostic.
ROTAZIONE
A parità di priorità l’accensione segue l’ordine numerico dei generatori per la prima accensione, mentre per le successive accensioni i generatori vengono fatti ruotare:
PHOTO TBD
Quindi nell’esempio sopra riportato alla prima accensione l’ordine saràROTATION
With equal priority, ignition follows the numerical order of generators for the first ignition, while for subsequent ignitions the generators are rotated:
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So, in the example above at the first ignition the order will be:
G1 → G3 → G2 → G4
Alla seconda accensioneAt the second ignition:
G3 → G1 → G2 → G4Attenzione: la produzione di Acqua Calda Sanitaria non risponde all'algoritmo di cascata di potenza
Warning
Domestic Hot Water production does not respond to the power cascade algorithm.