C.9 Message Examples C.9 Message Examples Below are some examples of command and response messages. u Reading Drive MEMOBUS/Modbus Register Contents Using the function code 03H (Read), a maximum of 16 MEMOBUS/Modbus registers can be read out at a time. The following table shows message examples when reading status signals, error details, data link status, and frequency references from the slave 2 drive. u Loopback Test Function code 08H performs a loopback test. This test returns a response message with exactly the same content as the command message and can be used to check the communications between the master and slave. User-defined test code and data values can be set.
The following table shows a message example when performing a loopback test with the slave 1 drive. MEMOBUS/Modbus Communications C SIEP C710606 33A OYMC AC Drive – J1000 User Manual 197 Command Message Response Message (normal) Response Message (fault) Slave Address 02H Slave Address 02H Slave Address 02H Function Code 03H Function Code 03H Function Code 83H Starting No.
Upper 00H Data Quantity 08H Error Code 03H Lower 20H 1st storage register Upper 00H CRC-16 Upper F1H Data Quantity Upper 00H Lower 65H Lower 31H Lower 04H Next storage register Upper 00H CRC-16 Upper 45H Lower 00H Lower F0H Next storage register Upper 00H Lower 00H Next storage register Upper 01H Lower F4H CRC-16 Upper AFH Lower 82H Command Message Response Message (normal) Response Message (fault) Slave Address 01H Slave Address 01H Slave Address 01H Function Code 08H Function Code 08H Function Code 89H Test Code Upper 00H Test Code Upper 00H Error Code 01H Lower 00H Lower 00H CRC-16 Upper 86H Data Upper A5H Data Upper A5H Lower 50H Lower 37H Lower 37H CRC-16 Upper DAH CRC-16 Upper DAH Lower 8DH Lower 8DH