Control of Blinds

I've not got much experience with C-Bus blind control and a customer has asked whether I can arrange for their blinds to be set at various levels rather than fully open or shut. I've noticed that their existing set-up uses a Bell Press action on 2 keys - one down and one up for each blind. Having read some of the posts on this forum on blind control I'm a little concerned about damaging motors and would like to know what is the preferred and simplest method of doing this using exiting relay channels i.e key function or logic or both.

 

Setting blinds to levels

Hi Harro,

As there is no way to feedback the current position of the blind, it will be pretty tough to set the blinds to predetermined levels and get them consistently to the right spot.

Your best bet is probably to start from a known position (ie. fully open/closed) then run them on a timer which cuts out when the blinds reach the right level.

You could do this in logic and trigger it from a single button, but the user will see the blinds go from whatever level they are at to fully open/closed, then to the required level, which is probably not the effect they want...

Here's what i'd do if i had a logic engine and some time:
1. Set up a Trigger Group with an Action Selector for each level you need.
2. Have a button on the key unit to transmit each Trigger Group/Action selector.
3. Have Logic set up to receive the Trigger Group/Action Selector and run the motor in the right direction for the time required to move from the current level (known by the last Action Selector received) to the required level.
4. At a regular time (eg. 3am once per day/week or something...) run the blinds to fully open/closed (where the limit switch will catch them) then back to the current position. This will tidy up any drift in level you get due to run times between levels not being quite right.

Have i made your life difficult enough yet???

Cheers,
Mark.

 

There might be another option:

We have a roller blind motor with built in radio receiver.
With the handheld remote (NOT with the C-bus interface) you are able to programme 2 intermediate positions. These positions are programmed inside the motor with a position counter, NOT a timer. So wherever you activate the positions from, the motor will accurately drive to them.

The interface needs to be activated by 240V switching, one for up, one for down.
Momentary down, runs motor down.
Momentary up, runs motor up.
"double click" up, runs motor to intermediate position 1
"double click" down, runs motor to intermediate position 2
Momentary command in opposite direction the motor is currently running in stops the motor.

The radio system is based on 915.3 MHz which has lesser range than 433MHz (10milliWatt compared to 10 - 25 milliWatt depeding on system used), however is much less interferred. Therefore the interface needs to be close enough to the radio motor.