January-13th-2020, 03:50 PM
(This post was last modified: January-13th-2020, 03:51 PM by Armin@netPI.)
Hello Carsten,
if you want to use RS485 for communication then you need to know which device is the master and which the slave. This is how Modbus RTU works.
I suppose your PLC is the modbus slave , or isn't it? I don't know. You need to get this information from the PLC. Here I can't help.
netPI - depending on the Node-RED node you use - can be either master or slave on RS-485 NPIX.
A statement to the RS485 LEDs: Since this interface is just solving the physics there is in no way a definition whether the protocol Modbus goes across it, nor the protocol M-Bus, Bacnet or any other serial protocol. This is all decided by the application side that is using the NPIX module during runtime ... so then a question back: how shall then the LED automatically know how to behave on the different type of protocols in use and when to be red or green or on and off. This can only be the responsibility as well of the application that uses the interface. This is why the LED of the NPIX Modules are free programmable.
I have no working example of Modbus RTU communication - respectively a Node-RED example. In best case it is just using the preinstalled Modbus client/master node within the Node-RED node catalogue. Client/Master if your Mitsubishi PLC is slave/server ... which you need to get out from somewhere as information
Thx
Armin
if you want to use RS485 for communication then you need to know which device is the master and which the slave. This is how Modbus RTU works.
I suppose your PLC is the modbus slave , or isn't it? I don't know. You need to get this information from the PLC. Here I can't help.
netPI - depending on the Node-RED node you use - can be either master or slave on RS-485 NPIX.
A statement to the RS485 LEDs: Since this interface is just solving the physics there is in no way a definition whether the protocol Modbus goes across it, nor the protocol M-Bus, Bacnet or any other serial protocol. This is all decided by the application side that is using the NPIX module during runtime ... so then a question back: how shall then the LED automatically know how to behave on the different type of protocols in use and when to be red or green or on and off. This can only be the responsibility as well of the application that uses the interface. This is why the LED of the NPIX Modules are free programmable.
I have no working example of Modbus RTU communication - respectively a Node-RED example. In best case it is just using the preinstalled Modbus client/master node within the Node-RED node catalogue. Client/Master if your Mitsubishi PLC is slave/server ... which you need to get out from somewhere as information
Thx
Armin
„You never fail until you stop trying.“, Albert Einstein (1879 - 1955)
