I am using:

• TIA Portal v20

• CPU 1515F-2 PN (6ES7 515-2FM02-0AB0)
  

• Drive: Digitax M750

• Connect v2.23.1.1 for servo drive configuration

I am trying to use the function blocks provided by Nidec via the Connect software. However, when I attempt to download the program to the PLC, I get an error stating: "Tag 'xxx' not defined" from these function blocks (message 604:4342).

I have followed this Youtube tutorial and also checked the manual included with Connect (see attached file), but the issue persists.

Does anyone have any suggestions for a possible solution?

Thanks for your answer. 
No UDT's are used. But I solved the problem by manually going into the function blocks that read/write to the drive. The ones provided by Nidec. And did a find and replace, then it worked.

Absolutely, that's something I've been thinking about. According to the manual, you should copy the FB and change the hard-coded I/O addresses. If you want the same type of block for the next axis.

0_Einstein

Since you are talking about an FB (function block), might I suggest changing the hard-coded values to input and output parameters so you can use the same block for multiple Digitax devices.  Otherwise, you will be limited to one device per FB (because of the hard-coded I/O addresses).

Eriksson_3535

Thanks for your answer. 
No UDT's are used. But I solved the problem by manually going into the function blocks that read/write to the drive. The ones provided by Nidec. And did a find and replace, then it worked.