ljean
commented
7 years ago Hello,
Modbus protocol is between a master, which is sending some queries to pull the data, and a slave which is receiving these queries and is hosting the data.
The simulator is hosting one or several slaves. It will answer the Modbus queries sent by masters.
It has a few built-in commands for add, remove slaves and blocks and set/get values. A block is not a Modbus concept. In this lib, it correspond to a set of values.
You can have a look at https://github.com/ljean/modbus-tk/blob/master/modbus_tk/simulator.py#L179
The Simulator base class can be inherited for creating your own Simulator. I did something like this in the "MySImu" example https://github.com/ljean/modbus-tk/blob/master/examples/mysimu.py
In this example, I create a block of 100 registers for slave 1. There is also 2 additional custom commands cv,set_pi (cv is a shortcut version of set_value, set_pi show how to handle float values)
Then If run the example, it will start a TCP server, add slave 1 and a block of 100 registers.
Then you can enter on the commands in the console. For example :
set_values 1 "foo" 10 2wil set value 2 to the register at address 10 (block "foo") of slave 1
If you query this register with a modbus master (see tcp master example) you should see value 2.
I hope it helps Best luc
runflowcode
Hi,
I am trying to understand how to write/read via modbus, and not sure how to begin testing. There's a simulator you created that may be helpful to me in understanding. Would you be able to give me some pointers in using the simulator.
Thank you in advance.