Modbus and TSX 07 Nano Register Address


Thread Starter

Glenn Harris

I am currently writing my first HMI using the Automated Solutions Modbus master to close coils in a Modicon TSX 07 nano PLC, also to access an internal memory word %MW05

I am looking for information as to how to use modbus addressing ie


00000-09999 01 COIL STATUS
10000-19999 02 INPUT STATUS
30000-39999 04 INPUT REGISTER
40000-49999 03 HOLDING REGISTER

to access the address register in the Modicon TSX 07 nano PLC. I am not able to use the data addressing above to get the right information from the nano using it's system ie

%M0 to 127 = Internal Memory Relays
%MW0 to 255 = Internal Word


Also any information as to how to make a cable connection would also be appreciated. The extension port is labled A, B and SG, there is no information as to whether A is Recieve and B is Send or reverse.

Any other help on how this can be achieved whould be greatly appreciated.


Glenn Harris
Mechanical Engineer.

Bill Szuminski

I recommend using the Tech Support Staff at Sq D, 1-800-468-5342, option #1. Explain to them what you have and don't mention Automated Solutions, they may point you back to them... Or, go to the site and scan for technical manuals.
Modicon has a pretty good Modbus Protocol manual that gives examples on message formats.

Rich Weekly, Branch Manager, Omaha / AE
Barr-Thorp Electric
4305 S. 94th Street
Omaha, NE 68127
[email protected] 402.331.3312
Any access to Modbus 0x register is map to %MX, e.g. 00001 map to %m0 and 4x register in Modbus protocol is map to %MW.

Both A and B are for transmitting and receiving. It's a RS485 port.

Hope this information helps.


Glenn Harris


Thank you for your responce, this information helped greatly. You may be amused that the official answer from Schneider is that the nano does not speak Modbus.

As far as the extension port goes I am wiring Pin 2 (Recieve data) on my PC COM1 serial port to A, and pin 3 (Transmit Data) to B, and finally pin 5 (Signal ground) to SG on the extention port, all other pins are ignored. This is the reason I asked the question as to which letter is send and recieve. Does wiring described above seem like the right approach to you?

Again thankyou for the help

Best Regards

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