Hello

I have a problem running two g120c inverters at the same time I add a sina_speed
block but it only works with a single inverter, when I try to upload 2 such
blocks, a message pops up as you can see in the screenshot, I have TIA 15.1 and
1214C PLC. Maybe i need to upgrade TIA to v16 or v17?

Your whole problem is, that you have added two blocks to the PLC that have the same block number. Most likely you've copied a block.

Within TIA / PLC the block numbers (as well as the names) need to be unique.

So just press "Yes" in this dialog, TIA will automatically re-number one of the blocks, problem solved.

Regards,
daviso