Function codes
The following "Function Codes" are supported:
| Function Code Name | Function Code | Subfunction Code | |
|---|---|---|---|
| Data Access (16-bit) | Read Holding Registers | 03h | |
| Read Input Register | 04h | ||
| Write Single Register | 06h | ||
| Write Multiple Registers | 16h | ||
| Read/Write Multiple Registers | 17h | ||
| Diagnostic | Clear Counters and Diagnostic Register | 08h | 0Ah |
| Return Bus Message Count | 08h | 0Bh | |
| Return Bus Communication Error Count | 08h | 0Ch | |
| Return Bus Exception Error Count | 08h | 0Dh | |
| Return Server Message Count | 08h | 0Eh | |
| Return Server No Response Count | 08h | 0Fh | |
| Return Server NAK Count | 08h | 10h | |
| Return Server Busy Count | 08h | 11h | |
| Return Bus Character Overrun Count | 08h | 12h | |
| Miscellaneous | Encapsulated Interface Transport | 2Bh | 0Dh |
| Read complete OD start | 65h | 55h | |
| Read complete OD next | 65h | AAh | |
| Read complete array/record start | 66h | 55h | |
| Read complete array/record next | 66h | AAh |