Lights Control Hardware (PLC)

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(igorua) #1

Hi Community!

I need some help in choosing hardware. Probably PLC but I’m not sure.

Here is my problem.
I have some loads - let’s say mostly lights. And I have different switches. I need to control lights with different types of switches (or with different behavior of switches):

  • with regular fixed ON/OFF wall light switch - turn on associated Light when switch is ON, turn OFF when switch is OFF
  • with regular fixed ON/OFF wall light switch - but in this case invert associated Light power state on every change of switch state (like in hotels)
  • with push button (not fixed) switch - invert associated Light power state on every button press. Most common way used for “smart” light systems.

Also this hardware needs to communicate and be controlled by OpenHab (via Modbus/TCP/Rest/etc) and support these options:

  • turn ON/OF load
  • get state of any Light channel: ON or OFF
  • get state / receive events of any switch: ON, OFF, long press (where applied), etc
  • (optionally) temporaly disable any of switches - so its associated Light channel can be controlled only remotely.

So in general logic is pretty simple - just ON/OFF Lights in different ways. See example:

I already have done all required wiring so this is not a problem. All cables go into one place.

Very preferably: programming software should work on Linux (I don’t have Windows/Mac).

I understand that all these requiretmens can be easy satisfied with home made hardware solution (Arduino or Raspberry Pi and bunch of relays) but I’m looking for something ready to use. So I will need only to program it without any soldering.

Maybe somebody can give me at least some examples of such hardware.

Thank you in advance!

For a long time I’ve been using some Modbus controller for controlling lights in part of my system. It works only with push (not fixed) buttons and cannot be programmed. It does its job but I’m looking for something more flexible.

(Rich Koshak) #2

I can’t recommend anything but why does all of this logic have to be coded in the device? All of these behaviors are easily handled using openHAB Rules.

(igorua) #3

It have to be on device in order to work without OpenHab. I.e. basic functionality of light switches must work without OpenHab.

Of course some extended logic like “trigger some scene with long press” should be definitely implemented on OpenHab. But in order to implement it I need this controller send me event when “long press” happens (just an example).

As I said I’m already using some simple Modbus controller. It changes Relay (Light) state by pressing Push button. And also it allows to change the same Light state via Modbus. This controller works all the time and doesn’t depends on OpenHab. Problems with this controller:

  • it doesn’t allow to detect “long presses”
  • it doesn’t allow temporary disable some switch
  • it doesn’t work with regular fixed (mechanical or bi-stable) switches and I don’t want to change these switches to push buttons
  • it cannot be reconfigured/programmed in order to implement something new
  • etc.

As far as I understand something like Siemens LOGO! is what I need but I’m not sure. And it is too expensive to buy it in order just to play.

I do think somebody already uses some solutions and may share experience.

(Rich Koshak) #4

I don’t know how you have it wired but many of us just use smart switches at the wall plate. There ore options from all sorts of different technologies including zwave, zigbee, wifi, and various wired options like KNX and of course PLC (I’m assuming you mean power line communication) like X10.

Some of these offer the ability to install the “smart” device behind the “dumb” wall switch so you don’t even have to worry about matching the rest of your switches. In all cases though, should OH go down, they still operate as “dumb” switches.

(igorua) #5

Thank you for answer @rlkoshak!

Here by PLC I mean Programmable Logic Controller. I know about option when you install “smart” switch behind existing “dumb” wall switch. But here I’m looking for different option.

My already existing lights wiring organized in star topology. Which means that I have separate wires for every switch and every lamp. And all these wires are going to one single place - electricity cabinet. So in this electricity cabinet I have wires from all my switches and lights.

That is why I’m looking for some device which will be placed in my electricity cabinet, will control all lights from single place, will satisfy requiretments from my first message in this post and of course will communicate with OpenHab.

BTW, after some research I found device which fits (I think) my requiretmens: M-DUINO PLC Arduino Ethernet 58 I/Os Analog/Digital PLUS.
But still I’m very interested in experience of other people from OpenHab Community. Maybe there are better/cheaper/simpler options.

(Rafał Różynek) #6

I am using Fatek PLC with extension modules and an Ethernet card (72 outputs and inputs, Modbus and Fatek protocol via UDP). All switches are monostable, bistable are useless in this case. I have a CAT5 ethernet cable in every switch socket.
All long clicks, two clicks etc. are programmed in the PLC, some timers also. openHAB integrates the Satel alarm, DMX, Xiaomi bulbs, temp/humidity sensors and activates several rules related to the astronomical clock, presence and so on. So if I do something in openHAB the basic functions works, all lights, roller shutters.
Wireless technologies are in some cases like pain in the back :slight_smile: for example, thick silicate walls, reinforced concrete ceiling. So I prefer to rely on cables.
One more thing big advantage of PLC is its stability.

(Markus) #7


I am also searching for this kind of solution with an star topologiy of wiring. But as i have to do it room by room in my Home i havent startet jet. My preferences are in principle the same espasicaly:

I will use the Siemens LOGO becaus of the name Brand and long term support.
A non name brand solution that i looked into is Denkovi Ethernet Relay boards and smartDEN IP Modules. There are also Application Notes for OpenHab.

In Comparison:
Simens Logo ~416€
24 Di
20 Do

Denkovi 1x (PLC) 1x (Relay Module) 1x (32 Input Module) ~429€
24 Di
24 Do
12 Ai
2 Ao
12 NTC

I would say Siemens ist the better option because of the name brand. But if you could use the extra inputs an outputs Denkovi might be interesting.

I would maybe do my Rollershutters with Denkovi because it is not mission critical.

Kind Regards

PS. sorry for my bad english i am from Germany

(Allen) #8

you can look at Siemens as well . S7-200 (PLC) or even the Logo! (Logical Programebel Relay)

And the Logo! has a binding for OpenHab .
Depends how deep your logic needs to be on the Controller ?

(Rossko57) #9

My approach to this has been to keep the hardware as stupid as possible, while allowing openHAB to “add the automation” on top.

My choices influenced by covering a commercial warehouse - large area, multiple “central” control boxes, avoid wireless tech - not the same as a home.

No PLCs. Simple pulse (step) relays at the central box, which allow standalone operation from multiple direct wired wall switches.
Cheap Modbus digital I/O units allow openHAB to monitor and control the relays.
Also take inputs from cheap wired PIRs.

It would have to be rather different if I needed dimmer functions though. Design choices there would be driven by what dimmer control tech was available at the right price. I suspect i would look at KNX.

(HomeAutomation) #10

I use mostly MOSBUS devices like ADAM6050 for this. They have own logic, which I do not use, and can be controlled by OH

(João Curado) #11


I use a Schneider electric PLC to do exactly what you want.

I’m in my phone now, I can send more information later.

See this old thread:


(igorua) #12

Not exactly what I’m looking for but still interesting.

@rossko57 can you please tell what pulse relays (vendor/model) you use? And how do you controll them?
In order to trigger state of pulse relay you need to close its control conacts for short period of time. But if pusle relay control contacs use 110V/220V then I guess you need another relay in order to triger it. :slight_smile: Is it correct?

(Rossko57) #13

Yes, that’s the safest way.

mains Pulse relay for DIN rail cabinet
although you could use a two-pole unit to allow signalling back to openHAB.

modbus unit, light duty relay contacts used as “pushbutton” for pulse relay

This is for a commercial site, not a home, 10A capacity is used - clonky is Good :smiley: