RS-232/485

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RS-232 and RS-485 are both serial communication protocols used for data transfer between devices. RS-232 is commonly employed for short-distance communication, typically under 50 feet, and supports point-to-point connections at lower speeds. Conversely, RS-485 is designed for longer distances, up to 4000 feet, and supports multi-point configurations with higher data rates. The key differences include their physical wiring setups, signal voltage levels, and maximum distance capabilities.

RS-232 is often found in older computer serial ports, connections to modems, and in certain industrial applications where simple point-to-point communication is sufficient. For example, connecting a computer to a printer or a microcontroller to a GPS module.

RS-485 is widely used in industrial automation systems, such as connecting PLCs (Programmable Logic Controllers) to various sensors and actuators. It is also common in building management systems (BMS), where multiple devices like HVAC systems, lighting controls, and other peripherals need to communicate over long distances in a multi-drop network configuration.

Functions

create

Instantiates a serial connection to a specific port.

In the options box, insert as an object the necessary parameters.

Parameter	Type	Default	Description
path	String		The system path of the serial port you want to open. For example, /dev/tty.XXX on Mac/Linux, or COM1 on Windows
baudRate	Integer	9600	The baud rate of the port to be opened. This should match one of the commonly available baud rates, such as 110, 300, 1200, 2400, 4800, 9600, 14400, 19200, 38400, 57600 or 115200. Custom rates are supported as a best effort per platform. The device connected to the serial port is not guaranteed to support the requested baud rate, even if the port itself supports that baud rate.
dataBits	Integer	8	Must be one of these: 5, 6, 7, or 8
lock	Boolean	true	Prevent other processes from opening the port. Windows does not currently support false.
stopBits	Number	1	Must be 1, 1.5 or 2
parity	String	'none'	Must be one of these: 'none', 'even', 'mark', 'odd', 'space'
rtscts	Boolean	false	Flow control Setting.
xon	Boolean	false	Flow control Setting.
xoff	Boolean	false	Flow control Setting.
xany	Boolean	false	Flow control Setting.
hupcl	Boolean	true	Drop DTR on close.

list

Lists all serial ports found on the system.

open

Opens the connection of the given serial port.

isOpen

getBinding

changeBaudRate

Changes the baud rate for an open port. Parameter baudRate can be set as 110, 300, 1200, 2400, 4800, 9600, 14400, 19200, 38400, 57600, or 115200.

write

Writes data to the given serial port and waits until all output data is transmitted to the serial port. Use the input box for data to insert the data you want to write. You can also use suffix to always add specific information at the end of the data you want to write.

If you need to transport a carriage return use <CR>, for linefeed use <LF> and for both together use <CRLF>.

read

Read data from a port.

close

Closes an open connection. If there are in-progress writes when the port is closed the writes will error.

onError

Reports about any errors

onData

Listens to data events

Parameter	Type	Default	Description
name	String		Name of the handler
handler	Function		Function to run as the handler
parserOptions	Object		Object that contains the following parser options.
parserOptions. delimiter	String	'\n'	Emits data after the delimiter is hit.
parserOptions. timeout	Integer		Timeout in ms after which data is emitted
parserOptions. byteLength	Integer		Number of bytes that must have been received until data is emitted.