Make Modbus/TCP gateway settings

You can turn the FP-I4C unit into a Modbus/TCP server that listens to the specified port.

All Modbus/TCP requests from clients will be translated into the protocol that has been set for the specified interface on the COM Interface page (MEWTOCOL, MEWTOCOL7, or Modbus).

When the internal interface INTERN is specified, TCP packets are not redirected to a physical device and the Modbus/TCP gateway setting has no effect. The interface INTERN refers to the addressable internal memory areas of the FP-I4C unit which are accessible via Modbus/TCP or the script function.

If Modbus/TCP gateway is enabled, you cannot enable Allow FPWIN Pro.

If Transparent is set for the COM interface, this setting is ignored.

If no restrictions are specified (default setting), no address can be read or written.

Go to the Ports and restrictions section and enable the Modbus/TCP gateway toggle switch for the desired port.
Go to the Memory area restrictions and mapping section and make the Modbus/TCP gateway settings.
- Memory area: Select the memory area of the PLC. Available areas: DT, FL (FP2SH only), LD, WR, WL, WY, WX.
- Start address, End address: Specify the first and last address of the range that can be accessed.
- Access: Select the type of access which is permitted: Read, Read/write, or Block.
- Modbus/TCP data type: Select the Modbus/TCP data type. Available data types: Holding register, Input register, Input, and Coil.
- Modbus/TCP offset: Set an offset to the Modbus/TCP start address. The setting value does not represent the actual Modbus/TCP offset value (e.g. a setting value of 0 for holding registers corresponds to Modbus/TCP address 400000 because the start address for holding registers is 400000).
  
  Modbus/TCP start addresses:
  - Holding registers: 400000
  - Input registers: 300000
  - Inputs: 100000
  - Coils: 0
Save your configuration.
When you have changed any settings, a Save button appears in the upper right corner of the screen. You can make changes on multiple pages and then save your settings.

Modbus/TCP translation rules:

The Modbus/TCP gateway supports the following function codes:
- 01 Read Coil Status
- 02 Read Input Status
- 03 Read Holding Registers
- 04 Read Input Registers
- 05 Force Single Coil
- 06 Preset Single Register
- 16 Preset Multiple Registers
Holding registers can be mapped to all types except WX.

Examples:
- Map 1000 holding registers starting from the first address to DT0 to DT999.
  
  Select DT for Memory area, enter an address range from 0 to 999, set the access type, select the data type Holding register, and enter 0 for Modbus/TCP offset.
- Map the next 1000 holding registers to LD0 to LD999.
  
  Select LD for Memory area, enter an address range from 0 to 999, set the access type, select the data type Holding register, and enter 1000 for Modbus/TCP offset.
- Map the first 1500 input registers to FL1000 to FL5999 (FP2SH only).
  
  Select FL for Memory area, enter an address range from 1000 to 5999, set the access type, select the data type Input register, and enter 0 for Modbus/TCP offset.
Coils can only be mapped to bit address areas WR, WL, WY.

Example:

Map the first 160 coils (10 words) to WR0 to WR9.

Select WR for Memory area, enter an address range from 0 to 9, set the access type, select the data type Coil, and enter 0 for Modbus/TCP offset.