Modbus Interface; Modbus Interface Register/Bit Map; Supported Modbus Function Codes - Hitachi HX-RIO3 Series User Manual

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9. MODBUS Interface

9.1. MODBUS Interface Register/Bit Map

• Register Map
Start Address Read/Write
0x0000 ~ Read
0x0800 ~ Read/Write
0x1000 * Read
0x1020 * Read/Write
0x1100 * Read/Write
0x2000 * Read/Write
*
The special register map must be accessed by read/write of each address (one address).
• Register Map
Start Address Read/Write
0x0000 ~ Read
0x1000 ~ Read/Write

9.2. Supported MODBUS Function Codes

Function Function
Code
1(0x01) Read Coils
(Read output bit)
2(0x02) Read Discrete
Inputs
(Read input bit)
Description
Process input image registers (Real Input Register)
Process output image registers (Real Output Register)
Adapter Identification special registers.
Adapter Watchdog, other time special register.
Adapter Information special registers.
Expansion Slot Information special registers.
Description
Process input image bits
All input registers areas are addressable by bit address.
Size of input image bit is size of input image register * 16.
Process output image bits
All output registers areas are addressable by bit address.
Size of output image bit is size of output image register * 16.
Description
This function code is used to read from 1 to 2000 contiguous status of coils
in a remote device. The Request PDU specifies the starting address, i.e. the
address of the first coil specified, and the number of coils. In the PDU Coils
are addressed starting at zero. Therefore, coils numbered 1-16 are
addressed as 0-15. The coils in the response message are packed as one
coil per bit of
the data field. Status is indicated as 1= ON and 0= OFF.
This function code is used to read from 1 to 2000 contiguous status of
discrete inputs in a remote device. The Request PDU specifies the starting
address, i.e. the address of the first input specified, and the number of
inputs. In the PDU Discrete Inputs are addressed starting at zero.
Therefore, Discrete inputs numbered 1-16 are addressed as 0-15. The
discrete inputs in the response message are packed as one input per bit of
the data field. Status is indicated as 1= ON; 0= OFF.
HX-RIO3 Series
Func. Code
3,4,23
3,16,23
3,4,23
3,4,6,16,23
3,4,6,16,23
3,4,6,16,23
Func. Code
2
1,5,15