questions about FM357-2

First, from the manual SIMATIC FM 357-2 Multi-Axis Module for Servo and Stepper Drives :

6.1.1 FM357_2L library

The supplied FM357_2L library contains several S7 programs (directories):

_ ”BF_V05xy_centralized”: All basic function blocks for CPU modules without PROFIBUS connection or for central use of the FM 357-2.

_ ”BF_V05xy_distributed”: All basic function modules for CPU modules with PROFIBUS connection or for both centralized and distributed applications of the FM357-2.

_ ”HPU”: Blocks which are supplied in addition to the basic functions and are required for operation with the HPU

_ ”HT6”: Blocks which are supplied in addition to the basic functions and are required for operation with the HT6.

Note

The application example ”zEn16_01_FM357-2_BF_EX” contains the basic function blocks from the directory ”BF_V05xy_distributed”.

Next, UDTs are "User Defined Types" that serve as templates for the creation of DBs. Once you have determined the structure of the UDT, you can create as many DBs you need based on a copy of that structure.

This is explained very well in chapter 9,3 of the manual SIMATIC Programming with STEP 7 V5.5

Functions provided with the FM module will require DBs that hold very specific data at various register offsets, and it is easier to provide you with a template than having you create it by hand.
So you can create a new DBin the Blocks folder when you need it to control and monitor your FM 357-2, but when you create it make sure it is based on the UDT template you need as described in the FM 357-2 manual.

Hope this helps,
Daniel Chartier