Beijer Electronics NA-9379 - Manual (Page 14)

NA-9379
Specification
Revision 1.02
FnBus PIO N/A Page 14
3.1.7. 8 (0x08) Diagnostics
MODBUS function code 08 provides a series of tests for checking the communication system between a client
( Master) device and a server ( Slave), or for checking various internal error conditions within a server.
The function uses a two–byte sub-function code field in the query to define the type of test to be performed. The server
echoes both the function code and sub-function code in a normal response. Some of the diagnostics cause data to be
returned from the remote device in the data field of a normal response.
• Request
Field name Example
Function Code 0x08
Sub-Function Hi 0x00
Sub-Function Lo 0x00
Data Hi 0x11
Data Lo 0x22
• Response
Field name Example
Function Code 0x08
Sub-Function Hi 0x00
Sub-Function Lo 0x00
Data Hi 0x11
Data Lo 0x22
Sub-function 0x0000(0) Return Query Data
The data passed in the request data field is to be returned (looped back) in the response.
The entire response message should be identical to the request.
Sub-function Data Field (Request) Data Field (Response) Description
0x0000(0) Any Echo Request Data
Sub-function 0x0001(1) Restart Communications Option
The remote device could be initialized and restarted, and all of its communications event counters are cleared.
Especially, data field 0x55AA make the remote device to restart with factory default setup of EEPROM.
Sub-function Data Field (Request) Data Field (Response) Description
0x0001(1) 0x0000 or 0xFF00 Echo Request Data Reset
0x0001(1) 0x55AA Echo Request Data Reset with Parameter
default
1)
0x0001(1) 0x55BB Echo Request Data Erase CoDeSys
program ²
)
1) NA-9379 and slot parameter will be the factory defaults value.
2) If all program is erased, NA-9379 change Stop mode. (about 10 sec)
Sub-function 0x000A(10) Clear Counters and Diagnostic Register
The goal is to clear all counters and the diagnostic register. Counters are also cleared upon power–up.
Sub-function Data Field (Request) Data Field (Response) Description
0x000A(10) 0x0000 Echo Request Data
PRELIMINARY