Difference between a shutter relay and change over relay

This may be a dumb question, but my understanding is that a shutter relay's purpose is to group 2 relays to in order to prevent these relays from telling a blind/shutter/curtain motor to rotate in both directions at the same time. Correct?

Reading the blurb for a L5504RVFC it seems to have the same purpose. This might be a very dumb question, but it seems like a very sensible question if you don't know the answer.

What am I missing?

Thanks

 

Hey mate,
From my understanding The blind shutter relay from a physical sense is basically half of a L5504RVFCP, ie 2 of the channels, internally wired in a interlock fashion.. However i believe the real trickery of the blind shutter relay is in its firmware, ie, how it controls those relays, particularly from cbus..

You can achieve similar functionality on the change over relay however you would need to write logic to achieve this generally.. It is how we used to do things before the CBus gods gave us the shutter relay..

Cheers..

 

Thanks Roosta, I think I understand. Basically the shutter relay has 2 relays that are interlocked and the firmware provides a mechanism to delay the unlocking of the locked relay in order to protect the shutter motors from being stressed by being rotated from one direction to the next too quickly. Correct?

So the L5504RVFC is different from the L5504RVF in that the "C" indicates that the relays are interlocked in pairs?

Thanks

Crispy

 

Yep your half way there.. There are 2 relays built into the blind controller, and they are configured so one relay feeds the other in an interlock so that the blind can not ever have its up and down 'on' at the same time.. The firmware does give the delay control etc, from cbus simple control..

So in the RVFC you get 4 relays that each have common, normally open, and normally closed contacts.. To get these to perfom similar to the blind controller you would need to physically wire from one of the relays contacts to the following relays contact, and then wire your blind up across the 2 relays contacts with power feeding into relay 1.. The exact config would depend on your blinds.. You would then need to configure the cbus software to control these 2 relays in order to achieve what you required, along with necessary expiry times etc and possibly even logic..

Have a gander through the install guide for the blind controller
http://www2.clipsal.com/cis/__data/page/428/L5501RBCP_C-BusShutterRelay-Installation2.pdf

Here is another doc that shows a bit about the change over setup
http://www2.clipsal.com/cis/__data/page/1985/5504rvfc_application_note.pdf

Also have a search for 'blind control' on the forum, theres tonnes of threads and info on this particular topic..

The 'C' in the L5504RVFC differentiates it from a normal RVF as it has change over relays(No - C - NC), opposed to just the No contacts of the RvF..

 

The C stands for changeover, meaning it has both normally open and normally closed contacts. It has nothing to do with interlocking.

My advise would be to just get the shutter relay, it works so much better than mucking around with ordinary relay channels (that's why it was created after all). It also integrates with the switches better as they know how to set the levels to do things like open, close, toggle and stop natively.

Cheers

Rohan

 

Thanks Roosta and Rhama,

Thanks for all the info, the fog is clearing. Actually I already have shutter relays but since my blinds are controlled through a somfy controller, I can't stop the blinds since they require an up/down within 2 seconds to cause them to stop at any point, which a shutter relay cannot do since the controller already inserts a small delay for protective purposes as well.

I have some of the L5504RVFC already sitting there unused so I was thinking i could use those instead of the shutter relays to solve my problem. It saves me buying 3 new L5504RVF units when I have 3 L5504RVFC sitting idle.

Thanks

Crispy

 

A change over relay has two states, on and off.

A blind controller also has smarts for a delay between change-over (to protect motors), a timer for "calculating" the blind position and as indicated, better integration into switches.

The timer feature - while not the best (as indicated by Ash in the past), allows you to tell a blind to go to say half open. You add the time it takes to open/close (e.g. 50sec) and then timer ramps a group up from 0-100% over the 50 seconds. So if you want to open half way you say open to 50% and the unit runs for 25sec (approx).

The time value also removes power from the relay on exipration. The blind motor will have a relay to cut power to the motor, a change over relay will leave power on the motor (unless you specifically remove it i.e. turn the relay off), whereas a blind relay will turn the power off after the internal timer expires. That means you should always set the time a little more than thte time to open/close so you can get full travel.

Hope this does not confuse you too much. Simply though - if doing blinds, curtains or roller shutters - use the blind controller.

Mick

 

If you are planning on keeping the somfy controller go with the L5504RVFC units as that is the only way you will be able to program both relays to close at the same time to give you your stop function. As mentioned in a previous post however, since you already have the shutter relays and the blind motors are wired back to the controller, it should be a simple process to remove the somfy controller and wire the motors directly to the shutter relays. That would give you full cbus control without having to write any logic.

 

Thanks Mick and Ashley,

Ashley I would remove the Somfy controller but then I lose the wind sensor as we discussed in a previous thread.

I am in the process of playing around with a 5504GI to deal with my existing weather station but I have a sever lack of time right now so in the mean time I want to sort out he louvres.


Thanks to everyone for all the advice.

Crispy