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General => Technical support => Topic started by: EtienneP on March 11, 2015, 06:11:41 PM

Title: Read function 03 and 04 register on same RS485
Post by: EtienneP on March 11, 2015, 06:11:41 PM

Hi,

I'll use an Nano10 to read and smal controler. I need to read in modbus RTU 9600 8,2,n with function 0x03 at adresse 10 the 23 first register. It's working!!!

Now in the same program I need to read on modbus the same module but with the function 0x04 6 bit.
Starting Adresse 0
Count 3.

Can I read with this 2 function on the same port?

Thank for Helping

Title: Re:Read function 03 and 04 register on same RS485
Post by: support on March 12, 2015, 10:00:53 AM

Yes, you can use SETSYSTEM 6,4 to change the function that READMODBUS uses from 03 to 04.

If you want to use both functions, then each time before a READMODBUS command is called, you run a SETSYSTEM 6,n  to change the function to 03 (n==3)  or 04 (n==4)

See the following for more info about READMODBUS commands:

http://www.triplc.com/yabbse/index.php?board=2;action=display;threadid=298