Basler Electric DGC-2020 - Manual (Page 436)

B-4 DGC-2020 Modbus
™ Communication
9400200990 Rev X
Preset Multiple Registers, Non-Broadcast & Broadcast
Preset Multiple Registers - General
QUERY:
This query message requests a register or block of registers to be written. The data block contains the
starting address and the quantity of registers to be written, followed by the Data Block byte count and
data. A device address is 0 for a broadcast query.
A register address of N will write Holding Register N+1.
No query data will be written (non-broadcast or broadcast) if any of the following exceptions occur:
•
Queries writing to Read Only or unsupported registers result in an error response with Exception
Code of “Illegal Data Address”.
•
Queries attempting to write more than 100 registers cause an error response with Exception
Code “Illegal Function”.
•
An incorrect Byte Count will result in an error response with Exception Code of “Illegal Data
Value”.
•
There are several instances of registers that are grouped together (signified as DP or TP) to
collectively represent a single numerical (vs. ASCII string) DGC-2020 parameter value. 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 an unacceptable 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 Error Check
RESPONSE:
The response message echoes the starting address and the number of registers. There is no response
message when the query is broadcast.
Device Address
Function Code 10 (hex)
Starting Address Hi
Starting Address Lo
No. of Registers Hi
No. of Registers Lo
CRC Error Check
Preset Single Register, Non-Broadcast & Broadcast
QUERY:
This query message requests a register to be written. A device address is 0 for a broadcast query.
No query data will be written (non-broadcast or broadcast) if any of the following exceptions occur: