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MODBUS Master Gateway

Owned by Kaitlin Luong
Last updated: Jun 07, 2024
1 min read

The CTM is linked to a SCADA server, positioned where the SCADA server is located.

MODBUS Slaves or Slave Gateways communicate with the Master Gateway, which in turn communicates with the SCADA server via RS232 or RS485.

A MODBUS Master Gateway is only necessary when the SCADA server communicates with the Slave devices via RS232. If the SCADA server can communicate via TCP/Ethernet, a Master Gateway is unnecessary.

Required Configuration Settings

Setting Name

Description

Value

Mode

Configure device to act as a Master Gateway

MODBUS Gateway Master

WAN Encapsulation

Protocol used to communicate with remote Slave Gateway

TCP or RTU over UDP - Should match Slave Gateway

Protocol

Protocol used to local talk to SCADA Server via RS-232/485

ASCII or RTU - Must match SCADA Server

Remote MODBUS Gateway Slaves

  1. Name

  2. ID

  3. IP

  4. Port

Master gateway requires a list of ALL Slaves it is trying to communicate with.

  1. User Friendly Name

  2. Remote Slave’s ID

  3. IP of Remote Slave Gateway

  4. Port used for this specific Slave

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