Modbus OH2 slider with dimmer

[Pawel (Pawel R)]

Hello all. Can someone give me some guide or example how to make slider that will work as dimmer for Modbus RTU device ? I build small Arduino Modbus slave that has one register (16bit) that drive PWM output… as for arduino its simple for me but OH2 config …not
I found on internet example for “Process roller shutter commands” and it works for buttons (depending from button i can send proper value 0 , 127, 245 ect ) - so Modbus cfg is OK
question - how should look “items” file? For now i have :

Dimmer LightControl “Dimmer [%d %%]” {modbus=“slave1:<2:>2”}

And items like on “demo” but i dont see change on RS232 modbus device (like OH dont send frame that change this register )

rule "Dimmed Light"
when
Item LightControl received command
then
if ((receivedCommand==INCREASE) || (receivedCommand==DECREASE)) {
var Number percent = 0
if(LightControl.state instanceof DecimalType) percent = LightControl.state as DecimalType

		if(receivedCommand==INCREASE) percent = percent + 5
		if(receivedCommand==DECREASE) percent = percent - 5

		if(percent<0)   percent = 0
		if(percent>100) percent = 100
         postUpdate(LightControl, percent);
	}

[rossko57]

You might need later Modbus binding version for Dimmer support

Modbus binding for openHAB-2

Great that you got it figured out! The proxy approach might not be needed anymore with the new transformation support out as experimental version I believe with the new version the dimmer items work straight away as the binding no longer ignores any item types. Since dimmer item type is decimal type, you might get it working without any transformation. Let me know if you decide to try it out. Best Sami

[Pawel (Pawel R)]

Hi thx for quick reply but can you be more specific what do you mean by “new version” ? I download openhab2 from website 1 week ago.
Also my gut tells me that i have problem with .rules … I’m on stage monkey when i type all i think is OK for my configuration.
How should look .rules for sendCommand for above example ?
because working part for at the end of rules there is switch and sendCommand
case “STOP”:{
sendCommand(myRSMoveStop, 127)
}

So case STOP send value 127 to modbus on Demo rules i have only “postUpdate” - its ok ?

[rossko57]

@Pawel

can you be more specific what do you mean by “new version” ?

Yes, I mean you need the Modbus binding version 1.10 to support Dimmer item types. This version is not included in stable OpenHAB2.

I don’t understand the rest of your post. if you use sendCommand, the binding should act on the command. If you use postUpdate, the binding will not act on the command.