Blind Triggering

Afternoon All

Further to my last post, i am still trying to find a way to control a 2 cable blind from a normal volt free relay pot

EG the kids bedroom blind Close Cable is connected to Port 1 and the Open Cable is connected to Port 2

I have created this in the logic engine of the touchpanels... will it work

once (GetCBusState("narrow lane farm", "Trigger Control", "Kids Bedroom blinds") = ON) and
(GetLightingState("Kids Bed C Blind 1") = OFF) and
(GetLightingState("Kids Bed C Blind 2") = OFF) then
begin
SetLightingState("Kids Bed C Blind 1", ON);
end;
once (GetCBusState("narrow lane farm", "Trigger Control", "Kids Bedroom blinds") = ON) and
(GetLightingState("Kids Bed C Blind 1") = ON) then
begin
SetLightingState("Kids Bed C Blind 1", OFF);
Delay("0:00:01");
SetLightingState("Kids Bed C Blind 2", ON);
end;
once (GetCBusState("narrow lane farm", "Trigger Control", "Kids Bedroom blinds") = ON) and
(GetLightingState("Kids Bed C Blind 2") = ON) then
begin
SetLightingState("Kids Bed C Blind 2", OFF);
Delay("0:00:01");
SetLightingState("Landing Corner Blind 1", ON);
end;


What im trying to achieve is that the neither Port 1 or 2 become live at the same time but work as i suspect the proper blind relay would ! Any help would be greatly appreciated as i am finishing the project tomorrow and have quite a few of these to write for the job

Cheers

Jon

 

As a little PS... the cables can remain live until the next actuation, this will not damage the blind eg... i can leave the relay closed till the next command

Thanks In advance for any help you can give

 

No, it won't work

Follow through the logic.

Assume both relays are off.

When the trigger is turned on, the first ONCE statement will become true. This will turn on relay 1.

Now look at the next ONCE statement. The trigger is still on and relay 1 is on, so it will execute and set relay 1 off, wait 1 second, then set relay 2 on.

This will then trigger the next ONCE statement which will set relay 2 off, delay 1 second and set relay 1 back on.

So whenever the second ONCE executes, the third ONCE will also execute and relay 1 will always be ON and relay 2 OFF.

Probably not what you wanted....

Also, for this to execute you would need to set the switch up as a bell press so pressing it sets the trigger and releasing it resets it or the ONCE will never re-trigger. Bell press it a bad idea because the logic only executes every 200mS and it is surprisingly easy the press and release a button in this time period resulting in the trigger being missed. Generally for logic it is better to get the switch to set the trigger and the logic to reset it after processing.

I'll try and post some code examples tomorrow. Past my bedtime.....

 

You will never be able to achieve what the Blind Relay achieves with software only.. Internally it is wired with a physical interlock so power to both up and down can never physically happen at the same time..

You can however replicate similar behaviour with software..

 

Hi JonBooth2,

To start with, I don't recommend this solution AT ALL and so this is just for informational purposes only and you should seek further advice before implementing a similar scheme etc........blah blah legal disclaimer etc.

In the days before the Shutter Relay was available, we would use a 5504RVFC changeover relay in conjunction with an RVF channel to provide the function on 240V blinds/external louvres or 12/24vDC (reverse polarity style) blinds.

On an RVF, one relay channel would be configured as say 'Kitchen Blind Power' and on the change-over relay, one relay channel would be configured as 'Kitchen Blind Direction'. You then defined two 'Logic Group' addresses (set to 'OR'), say 'Kitchen Blind Up' and 'Kitchen Blind Down' which you allocated using the logic tabs on the relays in Toolkit such that:

Kitchen Blind Up - Allocate to channel Kitchen Blind Power channel
Kitchen Blind Down - Allocate to channel Kitchen Blind Power and Kitchen Blind Direction channels

The 240V active would first transit the 'Kitchen Blind Power' RVF switch relay element and then enter the common terminal on the RVFC changeover relay that would then only select Up (Blind Power ON, Blind Direction OFF) or Down (Blind Power ON, Blind Direction ON). The 2 'output' lines from the RVFC changeover relay would go to the UP and DOWN active motor windings so as only one could be actuated simultaneously ie providing necessary safety interlocking.

Now you allocated Kitchen Blind Up and Kitchen Blind Down to your up and down switches on the switchplates. The Change-Over Relay ensured that only one direction control line on the motor was actuated at once.

You could emulate this same scheme for clients with only RVF channels free by purchasing an inexpensive DPDT relay and DIN rail relay base from your wholesaler (eg JR Turk had them, but interestingly, so did Jaycar - see picture below) but this scheme required a DC power supply to give power to actuate the relay for low voltage polarity reversal style blind motors (12V/24V) or a 240V DPST contactor for 240V motors, once again providing for the proper interlocking so as only one 240V active line is active at any one time.

The main problem with these schemes was that it took a while to loom it up and it had to be neat or there were so many lines it was hard to see what was happening. You also normally had an inline fuse on the blind motor to ensure it didn't over current. (see picture of one below I recently removed to replace with Shutter Relays)

I have included a circuit diagram I did for my own home from about 10 years ago, but this was for the Polarity Reversal 24VDC Somfy blind motors of the time whereas today, most blinds motors seem to be 240V.

So Jon, in the end you can do all that and have an inferior solution or do as I just did in my house, replacing 12 blinds circuits running these earlier schemes with Shutter Relays.

The Shutter Relay can also supports the eDLT far better as it can toggle up and down from the same button as it has a single Group Address for both up and down.

I note that you may have also considered using the 'interlocking' function within the relay units itself but I don't personally recommend this as a 'Failure Mode' I see sometimes in RVFs that have had a power spike/surge (or if a local override is triggered) is for all channels to be switched ON. This is why an external relay or RVFC for the change-over function is critical/recommended, but by far, the best solution is to just use the Shutter Relays.

Good Luck with that,

Brad

 

and the Circuit Diagram from my home documentation for the 24V Polarity Reversal Motors

As discussed, information relates to an old way of doing it, use of this method is at your own risk and is NOT recommended.

Use a shutter relay instead.


Brad