I have looked up multiple modbus-libraries on Github and read the example-codes.
Well until now I did not find an example that is plain simple to use.
I want to describe what I define as "plain simple to use":
Has an example-code where the master-code directly fits to a given slave-code
which means
use serial1 for the data-exchange
flash master-code into arduino mega 1
flash slave-code into arduino mega 2
connect both Arduino Megas over serial1-io-pins
serial monitor shows datatransfer in the sense of
at least a single bit in the data is toggling and the serial printing shows the changing value
or
having two buttons and two leds connected to the master
having a button and a led connected to the slave1
having a button and a led connected to the slave2
whenever the button1 of the master is pressed the LED of the slave1 lights up
whenever the button2 of the master is pressed the LED of the slave2 lights up
whenever the button of the slave1 is pressed the LED 1 of the master lights up
whenever the button of the slave2 is pressed the LED 2 of the master lights up
I am not addicted to use modbus RTU
if there exists a different library that does In one sentence:
send/receive bytewise data up to 128 bytes with a serial interface as the hardware
and using a protocol that enables to have multiple slaves I will use it.
My quick search for Arduino Modbus libraries on GitHub produced at least half a dozen different ones. Are you saying that in all the example codes for all those libraries, you didn't find a single one that meets your needs? Not even one that could be modified to meet your needs?
I am saying that the libs that I did find did not have
If "modifying" the sketch includes: learn all the details about this particular modbus-lib what each and every single parameter of each and every line of code that configures the bus.
That is my experience with many libraries. Emphasizing
learn all the details about the particular paremeters what each and every single parameter of each and every line of code that configures the bus to make it work.
I am asking for an either a very well documented demo-code which means the demo-code explains each and every single parameter in the function calls
or
A set of two / three demo-codes for master / slave that fit to each other 100.00%
do the hardware wiring, flash => runs
well this is what all my computers have installed and I am familiar with
(ironic - no of course not!)
master-example shows all functions
This program use 8 modbus functions and shows how to use it in loop.
slave-code
This example shows how to use ModbusSlaveRTU object in pair with ModbusMemory object.
what is the ModBusMemory-Object ?? sounds like something extra = extra work an time to find out. master and slave-code seem not to match each other
This sketch creates a Modbus RTU Client and demonstrates
how to use various Modbus Client APIs.
This sketch creates a Modbus RTU Server and demonstrates
how to use various Modbus Server APIs.
Now what is a client and server in case of modbus?? I thought it is master/slave?
is it the same?
Do the demo-codes fit to eacher? Seems not to be so
This is all that the slaves demo-code contains
void loop() {
mb.task();
yield();
}
??? So again the situation of analysing the library itself
It is called ESP8266-modbusRTU - not very promising I am looking for non-ESP-modbus-code
the name says it ModbusRTUSlave
no code for a modbus-master included
Additionally the repo says
Warning
ModbusRTUSlave is currently undergoing a redesign. Things may not work, or may not be corretly documented.
Did you find another one? If yes please post the link.
Does anybody use his own microcontrollers
which means both modbus-master and modbus-slave
For any library, if you find the documentation inadequate, the best advise is to start digging into its source code. Start with the interface which is typically specified in a .h file. The source code is, after all, the definitive explanation.
thank you very much for the link
indeed even the code-comment says
ModbusRTUSlaveExample
This example demonstrates how to setup and use the ModbusRTUSlave library (https://github.com/CMB27/ModbusRTUSlave).
It is intended to be used with a second board
running ModbusRTUMasterExample from
the ModbusRTUMaster library (https://github.com/CMB27/ModbusRTUMaster).
No slave support so may not be a complete solution for you, but does have UNO based software serial examples.
The NonBlockingModbusMaster library has the following features:-
– With suitably sized serial TX and RX buffers, it is completely non-blocking.
– No callback methods are necessary for single command non-blocking use.
– Uses RTU modbus and works with any Arduino Stream object
– Supports multiple device IDs.
– Has a simple command chaining facility to group commands together in a single executable non-blocking block.
– Has a retry() method for use when the command times out (or other some other error occurs)
– Has oneTimeDelay() method to insert an extra pre-command delay. e.g. when switching between device ID's
– Supports optional results processing functions that are called when the command completes.
– Runs on UNO with software serial while maintaining responsive Serial and other loop() processing.
I am stuck with the same problem. Among all these libraries, is there any specific library that supports STM32 chips (F070RBT6 one that I am using) using STM core in the Arduino IDE.
so may not be a complete solution for you, but does have UNO based software serial examples.