Solar buffer
simple Solar buffer
simple| This
function block realizes a simple solar control for
charging a single buffer. Either a pump via
switching hysteresis (digital) or a pump with analog or
PWM control can be used. The pump is switched on when the solar temperature is higher than the buffer temperature by the Hysteresis on and both the buffer and solar temperatures are below their maximum values. It is switched off again when the difference falls below the Hysteresis off or the buffer or solar temperature reaches its maximum value. Between the two thresholds the last state is kept, so Hysteresis on must be greater than Hysteresis off. With the pump switched on, the speed is set proportional to the temperature difference: speed in per cent = Gain x (solar temperature - buffer temperature), limited to 0 to 100 %. With a Gain of 5 and a difference of 20 K the pump therefore runs at 100 %. The value is present at the output Pump analog 0-100%; with the pump switched off it is 0. The control runs once per second. |
Inputs |
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| PU | Temp. buffer bottom | Temperature buffer bottom. Not linked: the block calculates with 0 °C, the switch-on condition is then almost always met and the pump runs permanently. This sensor must be linked. |
| SO |
Temp. solar |
Temperature solar (collector). Not linked: the block
calculates with 0 °C, the pump stays off. |
Outputs |
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| PD |
Pump
digital |
Pump digital on/off. |
| PA |
Pump
analog 0-100% |
Pump analog. As an alternative to
control via switching hysteresis, a pump with
analog control can be used at this output. |
Parameters |
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| Solar
max. |
Maximum temperature solar. If the temperature exceeds this value, the pump is switched off even if the buffer temperature has not been reached. | |
| Buffer
max. |
Switch-off temperature buffer. If the
buffer temperature exceeds this value, the solar pump is switched off. |
|
| Hysteresis
on |
Difference between solar and buffer
at which the control becomes active. |
|
| Hysteresis
off |
Difference between solar and buffer at which the control becomes inactive. | |
| Gain | Control setting; the higher the value, the faster the analog output changes with a change in temperature. | |