RS232 an X2

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HMIs, human machine interfacesPanel PC ET/MT-4x6...Electrical InstallationConnection ofRS-422 to X2


The X2 and X3 ports of our HMIs provide you with the option of using an RS-422 or an RS-485 bus, depending on the wiring. Below is an example of how this works with an RS-422.


The RS-422 (today: EIA-422) provides a data transfer interface with differentiated signals. The following illustrations shows how it should be connected:





In the RS-422 the only thing that is defined are the electric characteristics of the interface (OSI reference model, level 1). No standard exists for the connector pin assignment or the flow control protocol (control of data exchange, level 2), and you have to refer to the assignment information contained in the manuals of the connected devices for the exact wiring. The connected devices furthermore have to support the same protocol.


The RS-422 is mainly intended for a point-to-point connection. In process technology it is also used to realise a bus system (multi-drop) with (n) participants.


Classic point-to-point connection:




Multidrop connection:


Device 1

Device 2

Device (n)


See also:

Kapitelseite RS 422 Informations

Kapitelseite X2, RS-232, RS-422 and RS-485


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