146
Example:
Reads out the status signal, fault contents, data link status, and fre-
quency reference from the V7AZ (slave 2).
* Twice as much as the number of the reference message.
• Example of Loop-back Test (08H)
A reference message is returned as a response message without
being changed. This function is used to check communication
between the master and the slave. Any arbitrary values can be used
for test codes or data.
Example: Loop-back test of V7AZ (slave 1)
Reference Message
Response Message
(at Normal Operation)
Response Message
(at Fault Occurrence)
Slave address 02H Slave address 02H Slave address 02H
Function code 03H Function code 03H Function code 83H
Start
number
Upper 00H Number of data* 08H Error code 03H
Lower 20H First
holding
register
Upper 00H
CRC-16
Upper F1H
Quantity
Upper 00H Lower 65H Lower 31H
Lower 04H Next
holding
register
Upper 00H
CRC-16
Upper 45H Lower 00H
Lower F0H Next
holding
register
Upper 00H
(For error code 03H, refer
to page 157.)
Lower 00H
Next
holding
register
Upper 01H
Lower F4H
CRC-16
Upper AFH
Lower 82H
Reference Message
Response Message
(at Normal Operation)
Response Message
(at Fault Occurrence)
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
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