I am having issue on the Modbus Master. 

Modbus_Master Block has error 16#818C. Modbus_comm_load has no error 16#7000.

Please find the program. Refer the OB1, NW 8 & NW 9.

[snip]

Any one can advice what could be the issue ?

Thanks 

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Split from CM1241 Modbus RS-485 crash?.

Data Type struct seems the problem in your program. You can change that to Array of word and then compile and download and see whether you have the same error. Data Ptr cant take struct directly it seems. Just my thoughts. You can check and see whether changing the data type struct works?

Thanks,

Jay

Hi Jay,

I already tried array.. Refer the data block, "chiller data" (DB16 ) I use array of 10 integers ( i also tried to change word),.. in my program..

Still not working ...

Any advice ..

Senthilkumar.K

Hi Jay,

I already tried array.. Refer the data block, "chiller data" (DB16 ) I use array of 10 integers ( i also tried to change word),.. in my program..

Still not working ...

Any advice ..

Please ensure DB16 is not optimized.

error status = 818C 

The DATA_PTR parameter has an invalid pointer. Use a pointer to a bit memory area or a DB with the "Standard - compatible with S7-300/400" access type.

I am also getting Error 16#0000_818C. Can anyone tell what the error means?

I am unable to find help on Modbus_Master in the 'Information System'. Do I need to update or something? I am currently using TIA Portal V13 SP1.

Or can someone please send me an image of information page for modbus_master instruction.

Hi.

Just for future reference:

I got this same error for Modbus_Master [FB641] when the provided buffer array (at DATA_PTR) was in a not optimized DB. Once I put the buffer array into an optimized DB, it starts to work. This is the complete opposite of what you need to do at the older MB_MASTER block. So in short:

- MB_MASTER.DATA_PTR: use array placed into a not optimized DB

- Modbus_Master.DATA_PTR: use array placed into an optimized DB

Further advice:

If you are putting Modbus_Master and Modbus_Comm_Load into your own function block (for organizational purposes), use "Parameter instance" for instantiation. This way all the instance data will be external to your function block and all the helper function blocks (Receive_Config, Send_P2P, etc.) will appear in System blocks/Program resources as needed.

Beware, that you might need to create the DBs for both Modbus_Master and Modbus_Comm_Load manually (which will then also appear in aforementioned folders). After all this, you can provide created DBs as a parameter to your FB.

So why is it good to do this such a way? Because

- Modbus_Master_DB will be allowed to be not optimized (system default),

- Modbus_Comm_Load_DB will be allowed to be optimized (system default)

- DATA_PTR buffer array is also allowed to be optimized (FB requirement)

- Your FB DB will also be allowed to be optimized