Merge 2 items in one sitemap selection

Setup, Configuration and Use Items & Sitemaps
1

Hello,

I’m trying to combine two items in a selection but I can’t. I am using OH 3.4.

I am using a modbus device to control a fan.

The fan speed command is on a first modbus 40001 holding register (values to send: 3 = HIGH, 2 = MID, 3 = LOW).
The fan start/stop command is on a second 40002 holding register (values to send: 0 = OFF, 1 = ON).

My current working items in sitemap:

Selection icon=“fan” item=DATA__FAN_level_Value_as_Number label=“FAN []” mappings=[3=“10%”,2=“50%”,1=“100%”]
Switch icon=“fan” item=DATA__FAN_power_Value_as_Switch

I would like to have everything in a single selection of this style:

Selection icon=“fan” item=DATA__FAN_level_Value_as_Number label=“FAN []” mappings=[4=“OFF”,3=“10%”,2=“50%”,1=“100%”]

“4” send the command 0 to DATA__FAN_power_Value_as_Switch to power off the device. When we select one of the speed, we send the speed command to DATA__FAN_level_Value_as_Number and the command “1” to DATA__FAN_power_Value_as_Switch if it was “0”.

I searched but I don’t really understand how to do it.

Thank you in advance for your help.

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2

Use a proxy Item:

Maybe consider to use a more simple naming for Items:

Switch Fan_Power "Fan switch" {channel="modbus:...:40002"}
Number Fan_Speed "Fan Speed"  {channel="modbus:...:40001"}
Number Fan_Proxy "Fan"        // no link, it's a proxy

Sitemap:

Switch item=Fan_Proxy mappings=[0="OFF",3="LOW",2="MID",1="HIGH"]

rule:

rule "control fan"
when
    Item Fan_Proxy received command
then
    switch(receivedCommand.toString) {
        case "0" : Fan_Power.sendCommand(OFF)
        case "1" : {
            Fan_Power.sendCommand(ON)
            Fan_Speed.sendCommand(1)
        }
        case "2" : {
            Fan_Power.sendCommand(ON)
            Fan_Speed.sendCommand(2)
        }
        case "3" : {
            Fan_Power.sendCommand(ON)
            Fan_Speed.sendCommand(3)
        }
        default  : logWarn("fan","command not recognised: {}",receivedCommand)
    }
end

If the Fan is also switched independendly from openHAB, you will need a second rule to update the state of the Proxy item.

3

Hi Udo,

Thanks for the answer.

I implemented the solution you gave me. It more or less seems to work. I had managed to do almost the same thing with a proxy item using a rule with “if” command but he “cases” are much shorter and more effective. Great.

I have two concerns.

  • In the sitemap, I use a selection not a switch. Switch use too more space and don’t fit on the smartphone screen.
  • When I click on the “OFF” box in the sitemap, the command OFF is sent but immediately it returns to ON (see below). I don’t understand why. I’m using “switch” in sitemap for the test.

Sorry, for the long item names but as I will have more than one fan and room, I used a more complex naming.

2023-04-01 10:57:20.373 [INFO ] [openhab.event.ItemCommandEvent ] - Item ‘proxy_extracteur_control’ received command 0
2023-04-01 10:57:21.664 [INFO ] [openhab.event.ItemCommandEvent ] - Item ‘DATA__controleur_extracteur_power_local_2_Value_as_Switch’ received command OFF
2023-04-01 10:57:21.678 [INFO ] [penhab.event.ItemStatePredictedEvent] - Item ‘DATA__controleur_extracteur_power_local_2_Value_as_Switch’ predicted to become OFF
2023-04-01 10:57:21.685 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item ‘DATA__controleur_extracteur_power_local_2_Value_as_Switch’ changed from ON to OFF
2023-04-01 10:57:22.472 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item ‘DATA__controleur_extracteur_power_local_2_Value_as_Switch’ changed from OFF to ON

The modbus fan controler has a LCD screen where I can locally modify the settings and the feedback channel is not managed (as you suggested at the end of your post). I’ll also need the corresponding script.

4

Sorry for my first comment, I corrected the errors. I wrote a wrong address in the thing and I was updating the wrong register. Everything works including the “Selection” in the sitemap.

Only the feedback from the device to update the proxy is not working as I need a rule for that.

5

Easy :slight_smile:

rule "state of fan"
when
    Item Fan_Speed changed or
    Item Fan_Power changed
then
    var iStep = 0
    if(Fan_Power.state != OFF) {
        iStep = if(Fan_Speed.state instanceof Number) (Fan_Speed.state as Number) else -1
    }
    if(Fan_Proxy.state.toString != iStep.toString)
        Fan_Proxy.postUpdate(iStep)
end

If there is any issue with the reported value (i.e. no valid number), the Proxy Item will be set to -1, which can be used with a mapping (display only) to tell there’s an error.

6

Easy for your. :wink:

Me, I’ll still learning. :wink:

Still an error with the new rule.

Type mismatch: cannot convert from Number to int; line 3, column 191, length 77

Rule:

var iStep = 0
if(DATA__controleur_extracteur_power_local_2_Value_as_Switch.state != OFF) {
    iStep = if(DATA__controleur_extracteur_vitesse_local_2_Value_as_Number.state instanceof Number) (DATA__controleur_extracteur_vitesse_local_2_Value_as_Number.state as Number) else -1
}
if(proxy_extracteur_control_l2.state.toString != iStep.toString)
    proxy_extracteur_control_l2.postUpdate(iStep)
7

Oh, sorry, forgot an .intValue…

rule "state of fan"
when
    Item Fan_Speed changed or
    Item Fan_Power changed
then
    var iStep = 0
    if(Fan_Power.state != OFF) {
        iStep = if(Fan_Speed.state instanceof Number) (Fan_Speed.state as Number).intValue else -1
    }
    if(Fan_Proxy.state.toString != iStep.toString)
        Fan_Proxy.postUpdate(iStep)
end
8

Great!! It works both way.

The device is here. Very nice device. Several different models exist with various input/output configurations. It’s a bit of a jungle to find the right model for that matter.

They could have put the FAN “OFF” in the same register as the speed. It would have been easier. Currently, I have to use the general ON/OFF of the device for stopping the fan.

Thanks for your help.

Have nice week-end.