A RS485 bus consists of one master and multiple slaves. The twin consists of two conductors that are twisted together. The two jacks are for RS485 cable in and RS485 cable out. Most newer consumer electronics comes with an USB, Firewire or other high-speed communication port, however a lot of industrial and commercial equipment, both old and new, is made only with a RS485 or RS422 serial communications port. For communications, many of their products are equipped with an RS232 or RS485 serial port. Why use a RS232 - RS485 /RS422 converter? So what is a RS232 to RS485 converter? Xwire protocol over RS485 will allow cable runs of up to 1km - with suitable cable and grounding precautions- and up to 32 devices. The RS422 converter is used for data transmission, using balanced or differential signaling, it is mainly used in industrial and commercial environments since lots of process equipment and machinery have this protocol built-in. The reason is that the serial RS232 protocol is, even its old, a very reliable, stable and solid communication protocol, which can easily be implemented with existing industrial equipment. PCs are normally not equipped with an RJ11 socket for serial RS232 communications. With this boards, a CBL03 lines with RJ11 connectors can branch out to support an RS485 line consisting of three discrete wires.

All the other Master Bricks with RS485 Extension must not have a USB, Ethernet or WIFI connection (they can use a USB Power Supply). The Master Brick of each stack has to be the lowermost Brick (except if you are using a Power Supply). If you want to change something in your bus, e.g. add new Bricks or Bricklets, you have to power down the stack you would like to change, change it and repower it. To create a RS485 bus, stack the RS485 Extension on top of a Master Brick. The RS485 converter interface uses two wires for communication, one for transmitting and one for receiving data, which is referred to as a half-duplex communication converter. Two wire telephone cables will not function because in that case the ground signal levels on both sides will be floating. Wire up the RS485 stacks and set the termination switch on the first and last RS485 Extension in the bus to "on", as shown below. The normal way to implement this is with a two wire system with differential signal levels. Each device has a communication port with two terminals, which are indicated for the sake of convenience as A and B. In these two terminals the communication cable is connected so that all the devices that take part in the communication are connected in parallel.

RX led. When connecting that RS485 adapter to the PC's COM port, sending data to that port would make the RX led flash. 1. Connect the RS485 and your PC/Laptop through a LAN cable. The end resistance must be used only at the ends of the main cable. In order to avoid signal reflections, a 120 Ohm termination resistance must be fitted on each end of the main cable. Extending a RS232 line is done by converting the RS232 signal into RS422 and then back to RS232 at the remote end. Some of these converters can convert from RS232 to both RS485 and RS422 however many standard models only has one of the protocols. We also highly recommend using paired twisted cable for connecting most converters. This is a method for connecting multiple RS485 devices with each other over a two-wire network. This adaptor connects to the Xwire port on any SPLat controller and converts it to an RS485 interface.

The serial RS232 to RS485 converter and RS232 to RS422 converter units, also called serial converters, are small electronic devices used to convert a serial RS232 signal, (for example the COM port in older computers) into either RS485 or RS422 signals. You should see the Master Brick view with the identified RS485 Extension (see images below). RS485 master is the Master Brick which has a USB, Ethernet or WIFI connection to the PC running brickd. I am beginning to suspect that the board is not writing to the RS485 adapter correctly, or that pins are not mapped correctly. All slaves are connected to one another through a daisy chain. Due to loading limitations one of the best uses of a RS232 to RS422 serial converter might be in point-to-point communications, such as extending an existing RS232 line. And what is a RS232 to RS422 converter? A RS232 - RS485 converter is often used in industrial data acquisition and control applications where multiple serial devices communicate with each other through a converter. 2. Configure the IP of your RS485 and your computer to the same network address but different node address IP.