Introduction

lg-signage is module to control LG displays (LG digital signage, monitor signage) over LAN-TCP or RS232-serial connections. It is NOT for use with LG TV sets.

Main features

• different connection modes: tcp/serial/stream
• different schemas of connect-disconnect cycle
• command queuing and timing management
• events driven

Usage

const LG = require('lg-signage');

//send-receive data using TCP socket
const disp1 = new LG({host: '192.168.4.31', id: 1});
disp1.emitter.on('responseFromDevice', data => console.log(data));
disp1.process('sn?', 'input?'); //ask for serial number and active input

//send command using serial
const disp2 = new LG({path: 'com2', id: 2});
disp2.process('backlight 30'); //adjust display backlight to 30

LGDS Object

The primary exported object is LGDS. It extensively uses RAW object from raw-device as its prototype. Data neccesery to process commands is in lgds.xml file.

Constructor new LGDS(AddressObject, OptionsObject)

• AddressObject <Object> - required. Use only properties associated with the desired mode (serial, tcp, stream)
  • name <string> - default 'LGDigitalSignage'
  • id <number> - default 1. NOTEs for serial mode: all displays in RS-232 chain must have unique id number. If you set id: 0 in AddressObject, all displays execute commands, but no one of them return a response.
    //for serial
  • path <string> - required. Use valid serial path available in system.
  • baudRate <number> - default 9600
  • dataBits <number> - default 8
  • parity <string> - default 'none'
  • stopBits <number> - default 1
    //for tcp
  • host <string> - required. Use valid IP address
  • port <number> - default 9761
  • mac <string> - MAC address of display. Use only if you will need #wakeup command
  • broadcast <string> - broadcast address of used network. Use only if you will need #wakeup command on Windows
    //for stream
  • stream <Stream> - required. The stream must be opened read/write Node.js stream. This mode is used when multiple devices are chained with RS232 cables and connected to single system serial port. LGDS object does not care about the stream. You have to maintain stream yourself (open, close, error handling).
• OptionsObject <Object> - optional, default is {encoding: 'ASCII', wDuration: 500, rDuration: 300, disconnect: true, splitter: {regex: /x$/}}
  • encoding <string> - default 'ASCII'
  • wDuration <number> - default 500 ms. Inter-command period [ms] for set commands. A time for device to process command and to prepare and send a response.
  • rDuration <number> - default 300 ms. Inter-command period [ms] for read commands. A time for device to prepare and send a response.
  • disconnect <boolean|number> - default true. Connecion cycle scheme. Use true, false or timeout[ms]. True means close connection when command queue is empty, false means do not close connection, number means close connection after some ms. of connection inactivity.
  • splitter <Object> Used to select one among three supported transform streams which merge incoming data chunks and split it into valid messages. Only single property from delimiter, regex, timeout can be used. Default is {regex: /x$/}
    • delimiter <string> - use @serialport/parser-delimiter with string delimiter
    • regex <Regex> - use @serialport/parser-regex with regex
    • timeout <number> - use @serialport/parser-inter-byte-timeout with timeout. Response is completed if inter-byte time is longer then timeout. Please consider that timeout must be shorter than duration (inter-command period) and disconnect time (if disconnect use timeout scheme)

Method process(...commands)

Encode and send commands to device. You can use multiple commands in single call. Commands will be queued and executed FIFO.

Regular commands

Commands based on LG control protocol. Commands are strings in human friendly form command[?] [parameter]. Some examples:
power off - power off the display
backlight 30 - set backlight to 30 (0-100)
tilemode 2x3 - set tile mode (internal signal scaller)
input? - get active input
sn? - get display serial number.
Not all protocol commands are supported. NOT supported are commands with multiple parameters or extended commands ('sn' commands).
All supported commands with their usage are listed in lgds.xml file.

Internal commands

There are some internal commands which start with #. They are not sent to device, but are processed by LGDS object itself.

• #pause duration - Append additional pause between neighboring commands as number of miliseconds.
• #wakeup [duration] - Send WOL package to display. In tcp mode power on command will not work. You have to use #wakeup [duration] command insted. Default duration is 20000 ms.

Event: responseFromDevice

Emited when device response is properly decoded.

• response <Object>
  • dev <string> - device name
  • raw <Buffer> - not decoded raw response
  • req <string> - request id, used to identify response value. In most cases it is just a command name which response is for
  • status <string> - decoded response status. OK|NG. NG status means that command parameter was incorrect or command couldn't be executed in current display state
  • value <string|number|Object> - decoded response value. Returned type depends on request id (command name). See lgds.xml

Event: commandForDevice

Emited when command is properly encoded and sent to device. Of course only encoded property is sent to device itself.

• command <Object>
  • name <string> - device name
  • command <string> - a command itself, not parsed or encoded
  • encodedstr <string> - command encoded as string
  • encoded <Buffer> - command encoded as Buffer
  • duration <number> - time [ms] for device to process the command.

Event: connectionData

A data which comes directly from device port "as is". Not decoded, merged or chopped by splitter. Event is not emited in stream mode.

• data <Buffer>

Event: connectionStatus

Emited when device connection status changes. Event is not emited in stream mode.

• statusObj <Object>
  • dev <string> - device name
  • address <string> - device address as string
  • status <string> - connection status
  • more <string|Object> - additional status information