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Re: Issue with MODBUS register address configuration

Posted: Fri Dec 13, 2024 11:05 am
by mit2003
Hi Friends,

Today tested with different combinations to study the response of Modbus

slave addresses:1, Holding register starting address:0, number of Addresses:50 and working ststus:Proper data :P
slave addresses:1, Holding register starting address:10, number of Addresses:50 and working ststus:Return zero only :roll:
slave addresses:2, Holding register starting address:100, number of Addresses:99 and working ststus:Return zero only :roll:
slave addresses:2, Holding register starting address:0, number of Addresses:150 and working ststus:Proper data :P

Based on the observation, Irrespective of slave address, Starting address must be declare as '0' for getting proper response. Else get '0' as the response.

In case required data stored in the range of address 59100 to 59200 (that is 100 specific registers), we need very high memory :cry: in the controller to utilize correctly.

I can't able to understand the need for 'starting address of the modbus'.

Kindly correct me that where i am deviated from the actuals.

Thanks in advance for your valuable time and support.

Re: Issue with MODBUS register address configuration

Posted: Sat Dec 14, 2024 12:12 pm
by mit2003
Hi Friends,

If starting Address '10'. number of address '120' and Set holding registers 105,106 and 107, then the data returned to address 96, 97 and 98.
That is address mapped with offset value of starting address (10).

If starting Address '20'. number of address '120' and Set holding registers 105,106 and 107, then the data returned to address 86, 87 and 88.
That is address mapped with offset value of starting address (20).

I don't know how to configure data for the address 4361 to 4380 for getting data from 44362 to 44381 in real application.

Kindly help me to overcome this situation.
Thanks in advance for your valuable time and support.