knx actuators have per channel at least one object DPT1.008 (MOVE UP/DOWN) and another object DPT 1.007 (STEP UP/DOWN). Further you will find at least an object for last direction. But maybe there are two dedicated objects DPT 1.002 “upper/lower limit reached” or something else. Today most of the actuators provide absolute positioning and therefor have one object DPT 5.001 for setting the position and another DPT 5.001 for getting the position.
DPT 5.001 is SCALE 0% to 100% (step width ~ 0.4%)
There are other ways to control blinds or roller shutters for example by DPT 3.008 (step width). I don’t know if openHAB is capable to use this as I don’t use such actuators.
Of course you can omit a parameter, but then you have to explicitly define the DPT:
Rollershutter MyRollershutter "Rollershutter is at [%d %%]" {knx="1/1/1,5.001:1/1/3+<5.001:1/1/4", autoupdate="false"}
Here 1/1/1 would be "move UP/DOWN", 1/1/3 would be “set absolute position” and 1/1/4 would be “get absolute position”.
