Hello,

So i have a project and in my head it should be simple but i cant for the life of me figure out how to do it.

I have 2 devices that have a Volt free switched relay DPST. these are triggered by a float switch,
I need these to control 2 solenoids
The idea is that when both float switches are not activated, one of the Solenoids lets say Sol 1 is open, and Sol 2 is closed

When Float1 is activated i need Sol1 to close and Sol2 to open,
When Float1 is deactivated i need Sol1 to stay closed and Sol2 to Stay open, UNTIL
Float2 is activated, i need Sol1 to Open and Sol2 to close.
Then when Float2 is deactivated Sol1 Stays open and Sol2 Stays closed, UNTIL
Float 1 is activated.

Does this make sense?
When both Floats are activated (which is highly unlikely) then both SOL should idealy be closed...

Any ideas? i would like to do this with only Relays, Voltage supply is 24V and the SOL are both 24V coils

 

What is a Volt free switched relay, do you mean a latching relay?
Any info on these floats and relays?

 

Hello,

Apologies we call it a Volt Free Contact, Meaning the We can put any voltage in the COM and then the Relay will switch it to the circuit,
Basically its just a relay.

Info on relays - Which ever ones i need, this is begining stage of design, so any relays i need i will get,
Float Switch, - Reed switch capable of 100v 1amp. But these control the relays in my device ,(250V 1a)


Do you think this is all possible?

 

would like to do this with only Relays, Voltage supply is 24V and the SOL are both 24V coils

Is this 24 volts DC or AC?

 

DC

 

Is this a system to keep a tank filled ? Are the solenoids solenoid valves ? Do the valves open when fed with power ? When you say only relays does that exclude the use of diodes ?
Is this homework or a school project ? Are you allowed to use more than two relays or relays with more contacts than a DPST relay ?

Les.

 

Do you think this is all possible?

I believe this will work following the Truth Table.

 

Once initialized by the first operation, this should operate as you described.



EDIT: Revised per comment post #9. Also, re-arranged latch contact circuit.

 

Once initialized by the first operation, this should operate as you described.

View attachment 335355

I don't see a path for both solenoids ON when both Float switches are closed.
Both are connected in parallel but not to 24V.

 

To make the logic tracing and development a bit simpler, why not leave the diodes out until the design is completed. ALSO, why use signal diodes for spike protection?AND what iif the TS has AC powered solenoid valves?? AND, are those float switches all only single pole normally open??

I realize that diodes are a Serious Religion among some folks here, but coils only on paper do not produce any real surges.

 

The diodes on my post were there already when the symbols were pulled from my library. Besides, why would leaving them out make logic tracing simpler?
The TS mentioned they were 24 volt solenoids and it was a 24 volt DC supply.

 

I don't see a path for both solenoids ON when both Float switches are closed.
Both are connected in parallel but not to 24V.

That's easy to fix but doesn't seem to me like a requirement since it unlikely.

"When both Floats are activated (which is highly unlikely) then both SOL should idealy be closed..".

Anyway, lets see how the TS replies..

 

To make the logic tracing and development a bit simpler, why not leave the diodes out until the design is completed. ALSO, why use signal diodes for spike protection?

The diodes are for coil transient suppression.

AND what iif the TS has AC powered solenoid valves??

The TS has already wrote "DC".

AND, are those float switches all only single pole normally open??

The TS already wrote the float switch is a reed switch.

I realize that diodes are a Serious Religion among some folks here, but coils only on paper do not produce any real surges.

 

The TS specified DPST relays. I don't think it is possible to do it with these. I asked in post #6 if relays with different contact sets could be used but he has not replies to the question. These restrictions make me think that this is a homework question. If it is homework then our first tip should have been to convert his text into a truth table as sghioto has done in post #7. (This was also my first step when looking at the problem.)
He will not learn anything by just copying the solution.

Les.

 

The TS specified DPST relays.
Les.

The TS mentioned that he had two DPST relays on hand but later stated in post #3 he would get whatever relays were required. I don't think this is homework in the sense we normally think of.

 

Hi sghioto, you are right. I had wrongly remembered post #1 and thought it was a requirement that they had to be DPST relays.
Les.

 

Once initialized by the first operation, this should operate as you described.

View attachment 335419

EDIT: Revised per comment post #9. Also, re-arranged latch contact circuit.

Perfect! , I tried this with AC relays as thats all i had on hand, but worked perfectly!, will get some DC ones ordered and Send an image of the completed project!,
Thank you for all your help

 

Perfect! , I tried this with AC relays as thats all i had on hand, but worked perfectly!, will get some DC ones ordered and Send an image of the completed project!,
Thank you for all your help

Glad it worked.
Note the optional diodes suppress the transient generated by the relay coil and are applicable only to DC relays.

 

Glad it worked.
Note the optional diodes suppress the transient generated by the relay coil and are applicable only to DC relays.

Yeah perfect, will make sure i apply them when i get the DC Relays