Modbus TCP

The Modbus TCP connection allows the Intelligence Hub to connect to Modbus devices over TCP/IP, supporting both reading and writing of registers and coils. Below are details on the connection, input, and output settings.

Connection Settings

Setting	Description
Host	The hostname or IP address of the Modbus device.
Port	The port number the Modbus device is accepting connections on.
Unit Id	Controls the Unit ID in the header of the Modbus request. Default is 0.
Connect Timeout	Maximum time to wait for a connection to be established (1-300 seconds, default 10 seconds).
Request Timeout	Maximum time to wait for the device to respond (100-60000 ms, default 100 ms).
Zero Based Address	Whether 1 should be subtracted from any input’s address before being sent to the device. Defaults to enabled.
Modbus Byte Order	When enabled, uses big endian for 16-bit register values. Big endian treats the first byte received as the high byte in a register value. Disable for little endian sources. Default enabled.
First Word Low	When enabled, the first 16-bit register value of two consecutive registers is treated as the low word to make up a in a 32-bit value. When disabled, the first 16-bit register value is treated as the high word. The default is enabled.
First DWord Low	When enabled, the first two 16-bit register values of four consecutive registers are treated as the low double word to make up a in a 64-bit value. When disabled, the first two 16-bit register values are treated as the high double word. The default is enabled.

Input Settings

Setting	Description
Start Address	The starting Modbus address to read. Valid start addresses: 000001 (output coil), 100001 (input coil), 300001 (input register), 400001 (holding register).
Count	The number of consecutive addresses to read, beginning with the start address. f the count is 1, the value will be provided as a scalar, otherwise the value will be provided as an array of size Count
Unit Id	(Optional) Overrides the connection-level Unit Id. Default -1 uses the connection setting.
Bit Length	(Holding registers only) Specifies the length: 16, 32, or 64.
Treat as Signed	(Holding registers only) Specifies if the value is signed or unsigned.

Output Settings

Setting	Description
Start Address	The starting Modbus address to write to. Same valid start addresses as input. Valid start addresses included 000001 (output coil), 100001 (input coil), 300001 (input register) and 400001 (holding register). For holding registers, Bit Length and Treat as Signed fields are also available.
Count	The number of consecutive addresses to write, beginning with the start address. If the count is 1, the value written is a scalar, otherwise the value is an array of size Count.
Unit Id	(Optional) Overrides the connection-level Unit Id. Default -1 uses the connection setting.
Bit Length	(Holding registers only) Specifies the length: 16, 32, or 64.
Treat as Signed	(Holding registers only) Specifies if the value is signed or unsigned.