I would like to create an electronic circuit able to switch ON a relay (12V dc) when two contacts are open and switch it OFF only when both of them are closed. When this relay is switched on it starts heating of water in a buffer. And, of course, it stops heating when switches off…
I mean, one thermo-regulator closes its contact at a (lower) temperature (let us say 30 Celsius degrees – in the bottom part of the buffer) and remains closed until the temperature decreases below that temperature (it is set for cooling, and temperature is increased after relay is switched ON). A second regulator (set on heating – measuring a the middle buffer height) closes its contact at a higher temperature (let us say 50 Celsius degrees) and stays closed for a hysteresis period (some set degrees).
I need a relay (12V dc) to be switched on when both regulators have their contacts open (below 30 degrees), remaining on when first regulator closes its contact and switch it off when both regulators contact are Closed. After switching the relay Off the heating is stopped and temperature starts decreasing. So, the second regulator contact closes, but this must not determine switching the relay on, to restart heating. The heating must start again only after the first contact is open, too.
As a brief, the relay will be switched on when both contacts are open (below 30 degrees), remaining ON when the first regulator contact is closed, switching the relay OFF when both regulators contact are closed and stay OFF until the first regulator is open, when it should change the status (ON again). It must change its status only when both contacts are closed or open.
I try simulating the behavior of an existing heat pump automation system, for a backup one.
Probably, too many words but I only wanted to clearly describe the need...
I tried a schema using DC4011BE which does only the first part. After the second regulator contact is Open it closes heating, but it starts it again when the second regulator contact becomes open. And it must wait until the first regulator contact is also OFF…
Thanks in advance!
I mean, one thermo-regulator closes its contact at a (lower) temperature (let us say 30 Celsius degrees – in the bottom part of the buffer) and remains closed until the temperature decreases below that temperature (it is set for cooling, and temperature is increased after relay is switched ON). A second regulator (set on heating – measuring a the middle buffer height) closes its contact at a higher temperature (let us say 50 Celsius degrees) and stays closed for a hysteresis period (some set degrees).
I need a relay (12V dc) to be switched on when both regulators have their contacts open (below 30 degrees), remaining on when first regulator closes its contact and switch it off when both regulators contact are Closed. After switching the relay Off the heating is stopped and temperature starts decreasing. So, the second regulator contact closes, but this must not determine switching the relay on, to restart heating. The heating must start again only after the first contact is open, too.
As a brief, the relay will be switched on when both contacts are open (below 30 degrees), remaining ON when the first regulator contact is closed, switching the relay OFF when both regulators contact are closed and stay OFF until the first regulator is open, when it should change the status (ON again). It must change its status only when both contacts are closed or open.
I try simulating the behavior of an existing heat pump automation system, for a backup one.
Probably, too many words but I only wanted to clearly describe the need...
I tried a schema using DC4011BE which does only the first part. After the second regulator contact is Open it closes heating, but it starts it again when the second regulator contact becomes open. And it must wait until the first regulator contact is also OFF…
Thanks in advance!