Manual
Table Of Contents
- Table of Contents
- 1. ENVIRONMENT SPECIFICATION
- 2. NA-9379 (FNIO MODBUS PROGRAMMABLE I/O)
- 3. MODBUS/RTU INTERFACE (NOT TCP)
- 3.1. Surpported MODBUS Function Codes
- 3.1.1. 1 (0x01) Read Coils
- 3.1.2. 2 (0x02) Read Discrete Inputs
- 3.1.3. 3 (0x03) Read Holding Resgisters
- 3.1.4. 4 (0x04) Read Input Resgisters
- 3.1.5. 5 (0x05) Write Single Coil
- 3.1.6. 6 (0x06) Write Single Register
- 3.1.7. 8 (0x08) Diagnostics
- 3.1.8. 15 (0x0F) Write Multiple Coils
- 3.1.9. 16 (0x10) Write Multiple Resgisters
- 3.1.10. 23 (0x17) Read/Write Multiple Resgisters
- 3.1.11. Error Response
- 3.2. MODBUS Special Register Map
- 3.2.1. Adapter Resgister Mapping
- 3.2.2. Adapter Identification Special Resgister (0x1000, 4096)
- 3.2.3. Adapter Watchdog Time, other Time Special Register (0x1020, 4128)
- 3.2.4. Adapter Information Special Register (0x1100, 4352)
- 3.2.5. Adapter Setting Special Register (0x1600, 5632)
- 3.2.6. Expasion Slot Information Special Resister (0x2000, 8192)
- 3.3. Surpported MODBUS Function Codes
- 3.1. Surpported MODBUS Function Codes

NA-9379
Specification
Revision 1.02
FnBus PIO N/A
Page 18
Quantity of Write Hi 0x00
Quantity of Write Lo 0x02
Byte Count 0x04
Write Reg. Value#0 Hi 0x11
Write Reg. Value#0 Lo 0x22
Write Reg. Value#1 Hi 0x33
Write Reg. Value#1 Lo 0x44
• Response
Field name Example
Function Code 0x17
Byte Count 0x04
Read Reg. Value#0 Hi 0x11
Read Reg. Value#0 Lo 0x22
Read Reg. Value#1 Hi 0x33
Read Reg. Value#1 Lo 0x44
- In case of address 0x0800, 0x0801 output register value: 0x0000, 0x0000 changes to 0x1122, 0x3344.
3.1.11. Error Response
In an exception response, the server sets the MSB of the function code to 1. This makes the function code value in an
exception response exactly 80 hexadecimal higher than the value would be for a normal response.
• Exception Response Example
Field name Example
Function Code 0x81
Exception Code 0x02
• Exception Codes
Exception
Code
Name Description
01 Illegal Function The function code received in the query is not an allowable
action for the server (or slave).
02 Illegal Data Address The data address received in the query is not an allowable
address for the server (or slave).
03 Illegal Data Value A value contained in the query data field is not an allowable
value for server (or slave).
04 Slave Device Failure An unrecoverable error occurred while the server (or slave)
was attempting to perform the requested action.
05 Acknowledge The server (or slave) has accepted the request and is processing
it, but a long duration of time will be required to do so.
06 Slave Device Busy Specialized use in conjunction with programming commands.
The server (or slave) is engaged in processing a long–duration
program command. The client (or master) should retransmit the
message later when the server (or slave) is free.
PRELIMINARY