ComAp Inteli Mains NT BaseBox, Communications Manual

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IGS-NT Communication Guide
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9.2.5 Modbus communication
via IB-NT
Modbus communication needs to be enabled in settings via IB-NT config.
Modbus is available as Modbus TCP or Modbus RTU over RS485.
Note: For more information regarding IB-NT please see documentation InteliBridge
NT
Global Guide .
9.3 Modbus Protocol Description
9.3.1 Modbus TCP
Direct connection:
ETH
Port 502
Bridge connection:
IB-NT
Transfer mode TCP/IP
Function codes
3 (Read Multiple Registers)
6 (Write Single Register)
10 (Command)
16 (Write Multiple Registers)
The response to an incoming message depends on the network performace and on the controller
configuration. Typical response time is 25 ms.
Connection timeout is set to 15 seconds. If no message comes within the timeout then controller close the
connection.
Note: Data structure is the same as Modbus RTU. Modbus TCP adds 6 bytes header before data. CRC
calculation is not used in Modbus TCP.