Basler Electric BE1-700 Modbus Protocol - Manual (Page 21)

9376700991 Rev D BE1-700 Modbus™ Protocol 1-11
The response message contains the data queried. The data block contains the block length in bytes
followed by the data (one Data Hi byte and one Data Lo byte) for each requested register.
Response
Reading an unassigned holding register returns a value of zero.
Device Address
Function Code = 03 (hex)
Byte Count
Data Hi (For each requested register, there is one Data Hi and one Data Lo.)
Data Lo
.
.
Data Hi
Data Lo
CRC Hi error check
CRC Lo error check
Return Query Data
This query contains data to be returned (looped back) in the response. The response and query
messages should be identical. If the query is a broadcast (device address = 0), no response message is
returned.
Device Address
Function Code = 08 (hex)
Subfunction Hi = 00 (hex)
Subfunction Lo = 00 (hex)
Data Hi = xx (don't care)
Data Lo = xx (don't care)
CRC Hi error check
CRC Lo error check
Restart Communications Option
This query causes the remote communications function of the BE1-700 to restart, terminating an active
listen only mode of operation. No effect is made upon primary relay operations. Only the remote
communications function is affected. If the query is a broadcast (device address = 0), no response
message is returned.
If the BE1-700 receives this query while in the listen only mode, no response message is generated.
Otherwise, a response message identical to the query message is transmitted prior to the
communications restart.
Device Address
Function Code = 08 (hex)
Subfunction Hi = 00 (hex)
Subfunction Lo = 01 (hex)
Data Hi = xx (don't care)
Data Lo = xx (don't care)
CRC Hi error check
CRC Lo error check
Listen Only Mode
This query forces the addressed BE1-700 to the listen only mode for Modbus communications isolating it
from other devices on the network. No responses are returned.
While in the listen only mode, the BE1-700 continues to monitor all queries. The BE1-700 does not
respond to any other query until the listen only mode is removed. All write requests with a query to Preset
Multiple Registers (Function Code = 16) are also ignored. When the BE1-700 receives the restart
communications query, the listen only mode is removed.
Device Address
Function Code = 08 (hex)