Serial Port


This page displays the diagnostic data for the devices connected to the serial port.

Setting Procedure





From the Link150 menu bar, click Settings.

Opens the Settings menu.


From the Settings menu, in the Communication submenu, click Serial Port.

Displays the serial port settings options.


Select your mode, physical interface, transmission mode, baud rate, parity, termination, biasing, stop bits and response timeout.

Selects the serial port options.


If you select Slave mode, enter the IP addresses and TCP port for the remotely connected devices.

Enters the IP addresses and TCP port of the remote devices.


Click Apply Changes.

Updates the serial port settings of Link150 gateway.

Serial Port Settings




Mode(Device reboots on mode change)

Selects how the serial COM port on the Link150 gateway is utilized (master or slave).

NOTE: When you change the mode and click Apply, the Link150 gateway reboots and clears the device list configuration.
  • Master (Factory setting)

  • Slave

NOTE: ION protocol supports only Master mode.

Physical Interface

Selects how the Link150 gateway serial port is physically wired.

  • RS485 2-wire (Factory setting)

  • RS485 4-wire

  • RS232

Transmission Mode

Selects how data is transmitted over a serial connection.

  • For master mode:

    • Automatic (Factory setting)

    • Modbus ASCII

    NOTE: Transmission Mode is disabled for ION protocol.
  • For slave mode:

    • Modbus RTU (Factory setting)

    • Modbus ASCII

NOTE: Modbus Automatic mode allows you to communicate to Modbus RTU, Jbus, and PowerLogic (SY/MAX) slave devices on the same daisy chain.

Baud Rate

Used to select the data transmission speed over a serial connection.

  • 19200 bps (Factory setting)

  • 2400 bps

  • 4800 bps

  • 9600 bps

  • 38400 bps

  • 56000 bps *

  • 57600 bps *


Used to select if data is checked for accuracy using a parity bit.

  • Even (Factory setting)

  • Odd

  • None

Stop bits

Stop bits sent at the end of every character allow the receiving signal hardware to detect the end of a character and to re synchronize with the character stream.

  • Auto (Factory setting)

  • 1 bit

  • 2 bits

NOTE: Auto sets stop bit as 1 when you set Parity to Even or Odd and as 2 when you set Parity to None.

Termination *

Used to terminate the RS485 line in order to prevent reflections. Setting Termination to Enabled enables the termination resistor.

  • Enabled (Factory setting)

  • Disabled

Biasing *

Used to prevent invalid data bits by forcing the transmission line into a known state. The transmission line into the RS-485 port enters an indeterminate state when it is not being transmitted to. This indeterminate state causes the receivers to receive invalid data bits from the noise picked up on the cable.

  • Enabled (Factory setting)

  • Disabled

Response Timeout *

Used to select how long the Link150 gateway waits to receive a response from a serial device.

NOTE: The Response Timeout parameter is disabled if the Mode is set to Slave.
  • 3 seconds (Factory setting)

  • 0.1 to 10 seconds

Remote Device Connections (in slave mode only)

Used to define a list of Modbus TCP/IP addresses for the Link150 gateway to use during slave mode communications.


Port (in slave mode only)

Used to select the Modbus TCP/IP port of the remote device connection.

  • 502 (Factory setting)

  • 1–65535 available settings

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