Appendix B – Modbus Protocol
B-14 NMBA-01 Installation and Start-up Guide
06 Preset Single
Register
Presets a value into a single holding register (4X reference). When
broadcast, the function presets the same register reference in all
attached slaves.
Query
The query message specifies the register reference to be preset. Reg-
isters are addressed starting at zero: register 1 is addressed as 0.
The requested preset value is specified in the query data field. The
NMBA-01 uses 16-bit values.
Here is an example of a request to preset register 40002 to 00 03 hex
in slave device 17:
Figure B-7 Preset Single Register - Query
Response
The normal response is an echo of the query, returned after the regis-
ter contents have been preset.
Here is an example of a response to the query on the opposite page:
Figure B-8 Preset Single Register - Response
QUERY
Field Name Example
(Hex)
Slave Address 11
Function 06
Register Address Hi 00
Register Address Lo 01
Preset Data Hi 00
Preset Data Lo 03
Error Check CRC CRC (16-Bits)
RESPONSE
Field Name Example
(Hex)
Slave Address 11
Function 06
Register Address Hi 00
Register Address Lo 01
Preset Data Hi 00
Preset Data Lo 03
Error Check CRC CRC (16-Bits)
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