Rule to send message to Node

[FredRoot]

Hi,

I have this simple rule to test data tx to a node:

rule "Test"
when
        Item Test_Btn changed
then
        sendCommand(Test_Btn, "30;200;1;0;3;ON")
end

and Test_Btn is defined as the following item:

Switch 		Test_Btn  "Test Btn"

When I press the button, I get the following error:

18:18:34.161 [INFO ] [smarthome.event.ItemCommandEvent    ] - Item 'Test_Btn' received command OFF
18:18:34.182 [INFO ] [marthome.event.ItemStateChangedEvent] - Test_Btn changed from ON to OFF
18:18:34.199 [ERROR] [.script.engine.ScriptExecutionThread] - Rule 'Test': The argument 'command' must not be null or empty.

What does "The argument 'command' must not be null or empty" mean?

[TRS-80]

I came across this post while looking for some information, and I realize this post is quite old, but I wanted to resurrect it for a couple reasons:

• It looks like OP made a few posts and then never came back since 2018, so maybe they gave up (I know I have been there, more than once). I have come across a lot of posts like this while looking things up and I always find it quite sad that they never so much as received a single reply.

• There are almost 600 views, so clearly I am not the only one looking for this information.

Therefore, @FredRoot, if you read this, just curious if you ever got it sorted.

And for anyone else reading, OpenHAB has changed a bit in the meantime, but I am pretty familiar with it, and so I could post a working example should anyone need it. Although this is really more of an OpenHAB question, and therefore perhaps more appropriate for their forums.