Basler DECS-250, Instruction Manual

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9440300990 Rev J 201
DECS-250 Modbus™ Communication
•
There are several instances of registers that are grouped together to collectively represent a single
numerical DECS-250 data value (i.e. - floating point data, 32-bit integer data, and strings). A query to
write a subset of such a register group will result in an error response with Exception Code “Illegal
Data Address”.
•
A query to write a not allowed value (out of range) to a register results in an error response with
Exception Code of “Illegal Data Value”.
Device Address
Function Code =
10 (hex)
Starting Address Hi
Starting Address Lo
No. of Registers Hi
No. of Registers Lo
Byte Count
Data Hi
Data Lo
.
.
Data Hi
Data Lo
CRC Hi error check
CRC Lo error check
Response
The response message echoes the starting address and the number of registers. There is no response
message when the query is a broadcast (device address = 0).
Device Address
Function Code =
10 (hex)
Starting Address Hi
Starting Address Lo
No. of Registers Hi
No. of Registers Lo
CRC Hi Error Check
CRC Lo Error Check
Preset Single Register
A Preset Single Register query message requests a single register to be written. If the query is a
broadcast (device address = 0), no response message is returned.
Note: Only data types INT16, INT8, UINT16, UINT8, and String (not longer than 2 bytes), can be preset
by this function.
Query
Data will cease to be written if any of the following exceptions occur.
•
Queries to write to Read Only registers result in an error response with Exception Code of “Illegal
Data Address”.
•
A query to write an unallowed value (out of range) to a register results in an error response with
Exception Code of “Illegal Data Value”.
Device Address
Function Code =
06 (hex)
Address Hi
Address Lo
Data Hi
Data Lo
CRC Hi error check