chrisb4748

Q03 Modbus to Nanodac

5 posts in this topic

Hi,

I am having an issue with writing data to a Nanodac via modbus. I am able to read data from the Nanodac, but unable to send data across.

I am reading data from 2 different Nanodac's and want to be able to write to the both of them. 

I have two different read and write addresses for the Nanodac's.

Would like some advise on how to resolve this issue.

Many Thanks.

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Are you using Function code 16 -  Write multiple output registers? Sometimes if a parameter uses 32 bits you must use write using function code 16.

Is this the same type of data that you are reading?

Regards,
Garry

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No, I'm using function code 05/06 for my write and 02/04 for read. 

I am reading the same type of data, which the PLC can read. Its only my write function that is an issue.

Thanks

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https://www.eurotherm.com/index.php?route=product/download/get&download_id=137

7 MODBUS TCP SLAVE COMMS 

7.2.1 Function Codes  - MODBUS function codes 3, 4, 6, 8 and 16, defined in Figure 160, are supported and are fully described in Section 7.3, below.

Function codes 5, and 2 are not supported.

What is the actual information you are writing to the controller? If it is more than 16 bits long then use the function code 16.

Regards,
Garry

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Hi,

I am only writing over 2 D reg's. D100 & D105 which is going to be less that 16 bits.

I now see that the nanodac doesn't support 2 and 5 function codes.

Thanks

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