In the Omron Sysmac Studio you can define arrays to start at 0:
Array[0..9] of INT
Or define them to start at some non zero value:
Array[1..10] of INT
Which is pretty standard stuff.
When exporting tags to bring into the Omron Driver Tag Table in Ignition, I notice that all arrays are defined from 0…X instead of following their definition in the PLC. I figured this is fine, so long as the driver can successfully map the least significant element in the PLC, to element 0 in the Ignition tag table.
Had some strange behavior with it though, and was hoping to get some enlightenment on what is going on.
When I download code with arrays starting from 0, all is good, element 0 matches with element 0 in the PLC.
When i download code with the same array starting from 1, then the tags in Ignition are looking at the wrong element of the array, with an offset of 1.
I’ve even had the bizarre case where the driver seemed to flick between reading element 0 AND element 1 of the array, which i captured on video.
I should also point out I cannot manually change the tag table in Ignition to start an array at a non zero element definition.