Modbus support for transformations, roller shutter items, read-only items, write-only items, and others

Add-ons Bindings
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I had a chance to play, my first grown-up transform :smile:

To invert the sense of a Modbus discrete input:

Create the following javascript, call it mbinvert.js
(placed in /configurations/transform in OH1)

// function to invert Modbus binary states
// input variable i contains data passed by OpenHAB binding
(function(i) {
    var t = i ;      // allow Undefined to pass through
    if (i == 'OPEN') {
    	t = 'CLOSED' ;
    } else if (i == 'CLOSED') {
    	t = 'OPEN' ;
    }
    return t ;      // return a string 
})(input)

Note the ‘input’ to the script is pre-processed by the Modus binding into OPEN or CLOSED, suitable for the Contact Item it is bound to. The ‘input’ is not the raw 0 or 1 from the Modbus read.

Item defintion

//        This default Contact shows OPEN for Modbus discrete=1
Contact Standard "sensor [%s]" {modbus="slave1:0"}
//        This inverted Contact shows CLOSED for Modbus discrete=1
Contact Inverted "sensor [%s]" {modbus="<[slave1:1:trigger=CHANGED,transformation=JS(mbinvert.js)]"}

This generates logs and bus events only when the state changes.

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