help with simple interface circuit

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I have the following scenario. I have to do an automated blinds
installation. The control circuit for the blinds consists of the
following: A microcontroller which switches on two relays for up and
down, a single motor does the up and down. Two limit switches input to
the micro to prevent the rail from moving too far. The actual control
consist of 3 buttons. Which supplies three 12vdc signals back to the
microcontroller. Up, Down and Stop.

The problem I am having is that I need to integrate this into my
homeautomation device. It is a dynalite relay module. From which I
normally use two relays. One for up and one for down. Usually the
blinds I use only has neutral, a live for up and a live for down. So
the cabling have been done already. I've only got 3 wires running to
the blinds and I need to make this control circuit run with this.

Any suggestions for a circuit?

I've been thinking of using a relay which is wired common to 12V
normally closed to stop and normally open to up and then another relay
(or a double pole) with the common to 12V, normally closed to stop and
normally open to down.

The only problem I can see is that the stop signal will be sent to the
micro the whole time.

Otherwise I am going to have to reprogram the micro. It is an MDT and
I don't carry any knowledge that type.

Thank you

Johan

 

[Rich Grise]

I have the following scenario. I have to do an automated blinds
installation. The control circuit for the blinds consists of the
following: A microcontroller which switches on two relays for up and
down, a single motor does the up and down. Two limit switches input to
the micro to prevent the rail from moving too far. The actual control
consist of 3 buttons. Which supplies three 12vdc signals back to the
microcontroller. Up, Down and Stop.

The problem I am having is that I need to integrate this into my
homeautomation device. It is a dynalite relay module. From which I
normally use two relays. One for up and one for down. Usually the
blinds I use only has neutral, a live for up and a live for down. So
the cabling have been done already. I've only got 3 wires running to
the blinds and I need to make this control circuit run with this.

Any suggestions for a circuit?

I've been thinking of using a relay which is wired common to 12V
normally closed to stop and normally open to up and then another relay
(or a double pole) with the common to 12V, normally closed to stop and
normally open to down.

The only problem I can see is that the stop signal will be sent to the
micro the whole time.

Otherwise I am going to have to reprogram the micro. It is an MDT and
I don't carry any knowledge that type.

Assuming all of your signals are active high:

From new ctlr To micro

Up -------+-------------------- Up
| _______
+----\ \
| NOR >o----- Stop
+----/______/
|
Down ------+------------------- Down

Cheers!
Rich

 

[petrus bitbyter]

I have the following scenario. I have to do an automated blinds
installation. The control circuit for the blinds consists of the
following: A microcontroller which switches on two relays for up and
down, a single motor does the up and down. Two limit switches input to
the micro to prevent the rail from moving too far. The actual control
consist of 3 buttons. Which supplies three 12vdc signals back to the
microcontroller. Up, Down and Stop.

The problem I am having is that I need to integrate this into my
homeautomation device. It is a dynalite relay module. From which I
normally use two relays. One for up and one for down. Usually the
blinds I use only has neutral, a live for up and a live for down. So
the cabling have been done already. I've only got 3 wires running to
the blinds and I need to make this control circuit run with this.

Any suggestions for a circuit?

I've been thinking of using a relay which is wired common to 12V
normally closed to stop and normally open to up and then another relay
(or a double pole) with the common to 12V, normally closed to stop and
normally open to down.

The only problem I can see is that the stop signal will be sent to the
micro the whole time.

Otherwise I am going to have to reprogram the micro. It is an MDT and
I don't carry any knowledge that type.

Thank you

Johan

Guess that micro has nothing else to do but polling that UP/DOWN/STOP
switches. So if it sees "STOP" most of the time, who cares? The micro will
check whether the motor has been stopped and continue its polling. It will
not get tired or complain.

If you realy want to simulate the original buttons, you can do so using a
spdt and a dpdt relais. See below. Named them X and Y respectively. (Only
the contacts drawn, use fixed font.)

|+12V
|
|
|
o
\ x
\
o \o
| |
+-------+ |
| |
| +-+
| |
| |
o o
\ y1 \ y2
\ \
o \o o \o
| | | |
| | |
| | |
| | |
| | |
Stop Down Up

created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

petrus bitbyter

 

[ehsjr]

I have the following scenario. I have to do an automated blinds
installation. The control circuit for the blinds consists of the
following: A microcontroller which switches on two relays for up and
down, a single motor does the up and down. Two limit switches input to
the micro to prevent the rail from moving too far. The actual control
consist of 3 buttons. Which supplies three 12vdc signals back to the
microcontroller. Up, Down and Stop.

The problem I am having is that I need to integrate this into my
homeautomation device. It is a dynalite relay module. From which I
normally use two relays. One for up and one for down. Usually the
blinds I use only has neutral, a live for up and a live for down. So
the cabling have been done already. I've only got 3 wires running to
the blinds and I need to make this control circuit run with this.

Any suggestions for a circuit?

I've been thinking of using a relay which is wired common to 12V
normally closed to stop and normally open to up and then another relay
(or a double pole) with the common to 12V, normally closed to stop and
normally open to down.

The only problem I can see is that the stop signal will be sent to the
micro the whole time.

Otherwise I am going to have to reprogram the micro. It is an MDT and
I don't carry any knowledge that type.

Thank you

Johan

You have 3 wires to the blind operating motor.
Go simple. Lose the ucontroller, use the limit switches to
stop the motor, and do this:


+12 -------+-------------------------+
| |
+---o o---+
\
RY1-1 o---[Motor]---o RY1-2
\
+---o o---+
| |
Gnd -------+-------------------------+
|
Dynalite +12 --------[RY1]-----------+

When your automation controller tells the blinds to open, the
dynalite relay will energize RY1, which is installed at the
blinds motor location, and the blinds will open. The limit switch
will stop the motor.
When the automation controller tells the blinds to close, the
dynalite will drop the +12 on the line, so RY1 will drop and the
blinds will close. The other limit switch will stop the motor.

If the ucontroller is physically located at the motor
location, you already have power there. If the power
is there and you have thre additional wires for control,
just ignore the stop line, and run the dynalite signal
to a relay. Use the N/O & N/C points of the relay for
close and open. Again, the limit switchs stop the motor.


If you really want to complicate your life, use your automation
controller to select several different relays, each of which
selects a different tap on a voltage divider, and send that
voltage on one wire to the blinds assembly. Detect the voltage
and use it to determine how far to open the blinds.

Ed