Modbus

The Modbus connector is a field connector for TCP Modbus devices.

Connection settings

Setting	Description
IP Address	IP address of the Modbus host.
Port	TCP port of the Modbus host, usually 502.
Timeout	Timeout for connect, read, and write operations in milliseconds.
Between Messages Timeout	Delay between polling cycles in milliseconds.
Delay After Connect	Time to wait after opening the connection before polling starts.

Adding properties

Modbus properties are configured manually. Common fields are:

Property field	Description
Name	Display name of the property.
Address	Modbus address in standard notation.
Unit ID	Modbus slave/unit identifier.
Type	Data type such as Boolean, Short, Int, Float, Double, or String.
Direction	Input or output.
Polling Interval	Required for input properties.
Byte Order	Endianness/word order for multi-byte values.
Zero-Based Addressing	Controls whether the entered address is interpreted as zero-based or one-based.
Address Length	Required for string values.

Address ranges

The connector supports these Modbus regions through the entered address:

• 000001 to 065536: coils
• 100001 to 165536: discrete inputs
• 300001 to 365536: input registers
• 400001 to 465536: holding registers

Five-digit addresses are normalized to six-digit notation automatically.

Runtime behavior

• Input properties are polled on their configured interval.
• Output properties write values back to the Modbus device.
• The connector resolves the correct Modbus region from the address range.

Notes

• Use Zero-Based Addressing only when that matches the addressing convention of the target device documentation.
• String reads depend on Address Length, because the connector needs to know how many bytes to read.