Modbus

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This is the Modbus configuration used in [Action] -> [Modbus Communication].

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[Name]

Enter the name of the Modbus. You can use any name.

[Type]

Select the Modbus type.

RTU Master

RTU Slave

TCP Master

TCP Slave

[Serial Port]

Enter the serial port name. This field is only displayed when [Type] is “RTU Master” or “RTU Slave”.

[Baud Rate (bps)]

Select the baud rate (communication speed) for serial communication. This must match the settings of the communication partner. This field is only displayed when [Type] is “RTU Master” or “RTU Slave”.

[Parity Bit]

Select the parity bit for serial communication. This must match the settings of the communication partner. This field is only displayed when [Type] is “RTU Master” or “RTU Slave”.

[Stop Bit]

Select the stop bit for serial communication. This must match the settings of the communication partner. This field is only displayed when [Type] is “RTU Master” or “RTU Slave”.

[Data Bits]

Select the data bits for serial communication. This must match the settings of the communication partner. This field is only displayed when [Type] is “RTU Master” or “RTU Slave”.

[Unit ID]

Enter the Unit ID for the RTU Slave in the range of 1-247. The Unit ID, also known as Slave ID or address, is the unique ID number that a Slave possesses. When multiple Slaves exist on the network, the Master can communicate with a specific Slave using the Unit ID. This field is only displayed when [Type] is “RTU Slave”.

[IP Address]

Enter the IP address of the TCP Slave. This field is only displayed when [Type] is “TCP Master”.

[Port]

Enter the port number of the TCP Slave. The default port is 502. This field is only displayed when [Type] is “TCP Master” or “TCP Slave”.

[Connection Timeout]

Enter the maximum timeout duration to apply when connecting to the TCP Slave. If this time is exceeded, the connection is considered failed. This field is only displayed when [Type] is “TCP Master”.

[Max Connections]

Maximum number of Masters that can simultaneously connect to the Modbus TCP Slave. This field is only displayed when [Type] is “TCP Slave”.

[Register Size]

Enter the register size of the Slave. This field is only displayed when [Type] is “RTU Slave” or “TCP Slave”.

[Register Mapping]

Map [Number] type variables to the Slave’s register memory area. This field is only displayed when [Type] is “RTU Slave” or “TCP Slave”.

[Bit Size]

Enter the bit size of the Slave. This field is only displayed when [Type] is “RTU Slave” or “TCP Slave”.

[Bit Mapping]

Map [Digital] type variables to the Slave’s bit memory area. This field is only displayed when [Type] is “RTU Slave” or “TCP Slave”.

Grablo’s Modbus Slave memory does not distinguish between Input/Output and consists only of Register area and Bit area. Therefore, Coils/Discrete Inputs use the Bit area, and Holding/Input Registers use the Register area. Each memory address starts from 0.

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