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M340 NOE

Hello Everybody,


I will like to know why is necessary to use the NOE with a M340. I know when using the NOE it enables the IO Scanning but I know that the M340 has a modbus tcpip port and you can use the READ VAR to read register from other devices. What is the advantage of using the io scanning instead of the function block READ VAR? Does it really gives me an advantage using the NOE? Thank you very much for your time. 


Re: M340 NOE

Hello, The advantages of using IO scanner are: 1: Ease of use: configure (IOscanner) instead of programming (READ_VAR) 2: Faster read action/read response: Read_var takes several CPU scans to complete, while IOscan, can complete within a CPU scan (depending on refresh rate, CPU scan and responsiveness of device). 3: Number of concurrent IOscanner read/write actions higher than number of concurrent READ_VAR's. READ_VAR has a few advantages: 1: Possibility to READ %I, %IW and %M (Ioscanner limited to %MW only). 2: Possibility to change to communication function on-line, while IO scanner is changed offline and offline build/stop CPU/transfer has to be performed. br Rene Roozee