Please add the ability to manually select modbus (serial-rtu rs485) baudrate . I am not satisfied with the maximum baudrate of 115200kbps and now I have to manually change the speed in Machine.ini.

USB FTDI rs485 Converter allows to increase the baudrate up to 1000000kbps

Hi,
does the MODBUS device to which you are connecting go that fast? The fastest setting I've ever seen on a MODBUS device is 115.2kbps no matter how fast the serial
link is.

Craig

my device is not standard - it can

As you can see, with a baudrate of 1000000 and also using a USB-RS485 converter (FTDI chip) I was able to read two read functions in 26ms - which equates to about 40Hz.

I am very pleased with the result.

Although at baud rate 115200 - the same read functions are read in 33ms.
Which is also very good.

All this thanks to the ftdi chip - it has the lowest latency among all USB-rs485 converters

Hi,
MODBUS is quite a versatile communication protocol and has a huge established base......but it was never a blindingly fast protocol.
If you want really fast low latency comms then Ethernet or better, EtherCat, is the answer.

Craig

why you think about speed with rs485?
rs485 its not close to be real time ,its can monitor the device or command the device but always with delay its not way to  interpolate  several axiss
or some thing like that,so speed ....9600 its more then need

The serial speeds are actually coming from the MODBUS library we use.  I'll ask them to see if they will make it customizable.

Steve

why you think about speed with rs485?
rs485 its not close to be real time ,its can monitor the device or command the device but always with delay its not way to  interpolate  several axiss
or some thing like that,so speed ....9600 its more then need

I work with what I have. And I have a breakout board for ESS SSM Ethernet, which includes STM32 as a port extension. And the connection between them is just rs485.

The serial speeds are actually coming from the MODBUS library we use.  I'll ask them to see if they will make it customizable.

There is a possibility to use non-standard baudrate.
I already use these settings now and it works.
[Machine.ini]
Baud=1000000