cubloc:set_rs485:index

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====== Set RS485 ======

''Set RS485 channel, portNumber''
| //channel// | RS-232 channel (1 to 3)  |
| //portNumber// | Transmit enable port number   | 

RS485 allows you to link multiple Cublocs up to a distance of 1.2km. With
RS485, there must be 1 master and the rest must be slave devices. You
can use a chip such as the SN75176B or use an RS232 to RS485 converter module.

With RS485, transmitting and receiving data cannot occur simultaneously.
RS485 is known for being stable under noisy conditions.

You can refer to the following circuit schematic for connecting TTL signals
from a CB280 to the RS485 chip, SN75176B:

{{ :cubloc:set_rs485:setrs485.png?nolink |}}

RS485 communication needs a "Transmit Enable" signal to control when the
device is sending or receiving. There can only be one device transmitting
while all the other devices are in receiving mode.

==== Example: ====

When the PC is transmitting, all the slave devices can only receive data.

{{ :cubloc:set_rs485:setrs485_2.png?nolink |}}

The ''Set RS485'' command allows the CUBLOC or Cutouch to control the data
line whenever it wants to send or receive data. While the data is being
sent, the transmit enable pin will output active high. This will be done
automatically by the CUBLOC RTOS.

*NOTE: If you are using an RS232-to-RS485 converter and it supports
automatic mode, then you don’t need to use this command.


<code xbasic>
Set RS485 1,48     ' Set P48 as the transmit enable pin
</code>

{{ :cubloc:set_rs485:tren.png?nolink |}}

When using the Set RS485 command, the port chosen may not be used for other purposes.

{{ :cubloc:set_rs485:rs485network.png?nolink |}}

Please refer to the diagram when connecting multiple CUBLOCs or CUTOUCHes using RS485.

Please use a 120 Ohm terminating resistor for the device at the end.  The two 560 Ohm pull-up and pull-down resistors are required for proper communication.

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