@Steve-Mcl now you are working in NodeRED right can't you resolve this issue as i am new not knowing so deep as you and @Colin knows but still i didn't get the solution because you both are just telling me how to find solutions
Which modbus addresses you have to use is nothing to do with node-red. Which addresses you have to use is determined by the PLC, so you will need to find that from the Bradley PLC documentation.
Neither of us have used Bradley PLCs so we do not know the answer to the question. Once you have found which addresses to use we can help you to fetch those addresses in node-red.
@akshayjain we are not here to do you job for you.
As colin rightly states this is for node-red help.
Clearly this is a work related thing and you should either be competent with PLCs or you should hire someone who is.
In the interest of getting past this, I will do your job for you.
It took me less than 2 minutes to find this info and about 10 minutes to write it up for you.
A quick search on google for "allen bradley ml1200 modbus mapping" resulted in finding this manual
Page 140 states...
For more information on configurating your MicroLogix 1200 controller for
Modbus protocol, refer to the MicroLogix 1200 and 1500 Programmable
Controllers Instruction Set Reference Manual, publication 1762-RM001
Then I did a quick search on google for "1762-RM001"
The VERY FIRST RESULT was a link to the manual: https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1762-rm001_-en-p.pdf
Page 449 reveals how the AB PLC addresses are mapped to ModBus addresses...
Essentially, by default, it appears that
- N12:0 will be accessible by reading Address 1
(*1)using FC4 (Read Input Registers)
N13:0 will be accessible by reading Address 1(*1)using FC3 (Read Holding Registers) - N10:0 will be accessible by reading Address 1
(*1)using FC1 (Read Coil Status)
N11:0 will be accessible by reading Address 1(*1)using FC2 (Read Contact Status)
But that might NOT be the case - you will need to check the actual PLC settings - never assume.
NOTES...
(*1) Sometimes the PLC maps address 0 to modbus 0, sometimes it is modbus address 0 is PLC address 1, sometimes it is modbus address 1 is PLC address 0, it depending on how AB have mapped things
Already the second person on the forum has a problem with N7:10 in Micrologix 1200.
I wonder if the author of the thread also has a program in which the ML 1200 is Master and FC16 is used?
The configuration screen of the MSG command is a bit different, but the mapping principle is the same.
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