|You have not inserted the FC10 "EQ_STRNG" function in the project or the FC10 "EQ_STRNG" function has a different FC number.
This affects the following products and versions:
- S7 OpenMODBUS/TCP (V4.0 and V4.1)
- S7 OpenMODBUS/TCP PN-CPU
(V2.0, V2.1, V2.2, V2.3 and V2.4)
- SIMATIC Modbus/TCP RED V2 (V2.0)
This does not affect the following versions of the products listed above nor SIMATIC Modbus/TCP SENTRON PAC and SIMATIC Modbus/TCP PN CPU Redundant.
|Make sure that you have inserted the FC10 "EQ_STRNG" function in your project. This is available in the Standard Library of STEP 7 under "IEC Function Blocks -> Blocks".|
If the FC number is already being used in the user program, you must re-wire the FC10 "EQ_STRNG" function with the new FC number in the Modbus blocks.
|You have entered the license key only in the Data View of the license data block.
||If the license key is entered in the Data View of the license data block, this is overwritten with the initial value when the CPU is restarted. Therefore, you must enter the license key as the initial value in the Declaration View. Then the license key can be initialized in the Data View.|
|You have used the number 0 (zero) instead of the letter O in the REG_KEY.
||Make sure that the REG_KEY string consists only of letters.|
|Call the Modbus block in OB121.
This affects the following products:
- S7 OpenMODBUS/TCP
- S7 OpenMODBUS/TCP PN-CPU (only V2.2 and higher)
- SIMATIC Modbus/TCP RED V2
- SIMATIC Modbus/TCP SENTRON PAC
- SIMATIC Modbus/TCP PN CPU Redundant
|Remove call of the Modbus block from OB121.|