Logical ON/OFF with bus couplers?

Hi Guys,

I have just inherited a legacy site utilising bus couplers and PIR's as input units. The client has requested a control for an extractor and I am struggling to some up with a solution that doesn't involve a PAC.

Situation.

3 lighting channels Groups 1,2,3 on respective dimmer channels control via bus coupler

1 extractor channel Group 4 on a seperate relay

Desired result:

If any or all lighting channels are ON then the extractor is ON

If ALL lighting channels are OFF then extractor is OFF


Any suggestions would be gratefully received and if further info is required I will do my best to provide it

Thanks in advance


T

 

What happens when 1,2,3 are not all ON or OFF?

This is a question you need to ask.

If , say, 1,2 are ON, 3 are OFF always give you one result (eg, always On or always OFF), you have a static logic. Then you may solve it by logical gate diagram and hence program your relay.

If, say, 1,2 are ON, 3 are OFF give you different results, depending on what happens before hand (eg.no action), you have a dynamic logic, which can only be solved by PAC's logic engine.

 

If any of groups 1,2 or 3 are ON then the group 4 should be ON

If any combination of the groups 1,2 or 3 are ON then Group 4 should be ON

The only circumstance that Group 4 should be OFF is when groups 1,2 and 3 are OFF.

OR logic wouldn't be a problem if all channels were on the same output unit, but unfortunatly they aren't

 

Can't you use the logic in the relay.

See attached.

 

The output unit logic is intended for exactly your situation. In the DIN relay units, there is provision for up to 4 groups to be defined which may or may not be also used for controlling a relay channel.

You can even put a group in a relay unit with no logic selected so that the relay will store and contribute the group status on the network. This can be done to "reserve" a group address and prevent it from being used when using the LEARN feature to program units.

Don

 

Looks like Chris has nailed it already. Sometimes the simple solutions are the best.

Peter Brown

 

Thanks all.

Need a beating with the stupid stick I think, somehow got the idea inmy head that relay units could only use logical GA's which were present on the relay...

Will get it done this afternoon.

Thanks

T