Questions:
The different UDT data blocks belong to which block?
Answer:
In the block library for the Siemens S7 PLC there are four different UDT data blocks, UDT 90 - 93. It is useful to load all the four UDT blocks in the PLC in order to avoid problems.
- FB 90 and function FC90 require UDT90.
- FB 91 and function FC91 require UDT91.
- Function FC92 requires UDT92.
- Function FC93 requires UDT93.
Note:
Without the UTD blocks the OPC communication does not work. If the UDT blocks are not loaded in the PLC, an error message of the PLC will not be generated.
