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Connecting to UniPi extension
The UniPi extensions are convenient way how to extend the number of inputs and outputs at one location, or make accessible at another one.
The communication between controller and extension is via RS485 ports. The extension acts as a Modbus slave, which has an extended support in the Mervis.
HW connection
You need only two cables to connect the UniPi extension to the controller. Just interconnect the RS485-A port on the controller to RS485-A port on the extension and RS485-B on the controller to RS485-B on the extension.
For communication to work, you have to have identical serial port parameters on both sides - speed, data bits, stop bits and parity. Also each extension unit has to have unique address.
On model xS10, xS30 and xS40, you can set the speed, parity and address by DIP switches. On the xS50, only the address can be set.
