Read Contiguous 32-Bit Values; Figure 4-1 Read Contiguous 32-Bit Request And Response Message Formats - Honeywell UMC800 Reference Manual

Message Exchange Formats

4.2 Read Contiguous 32-Bit Values

Introduction
Figure 4-1 shows the Read request and response format for Function Code 2 - Contiguous 32-Bit values.
This operation lets you read a list of 32-Bit values from a specific block given the starting index number
and the number of values involved.
Message Formats

Figure 4-1 Read Contiguous 32-Bit Request and Response Message Formats

Header
Request Message
READ/WRITE
0 = Read
FUNCTION CODE
2 = Contiguous 32 Bit Values
NUMBER OF VALUES REQUESTED
FILLER BYTE: For Word Alignment
Response Message
ACKNOWLEDGE/
UNACKNOWLEDGE
09 = Acknowledge
0a = Unacknowledge
FUNCTION CODE
02 = Contiguous 32 Bit Values
(If response is Unacknowledge, then an error code is
returned instead of a function code. See Table 2-1.)
28
Byte 1 Byte 2 Byte 3
0
Data
NUMBER OF VALUES RETURNED
RS232 Communications Reference Manual
Byte 4 Byte 5 Byte 6
INDEX NUMBER
Index number of the desired
parameter within the selected block
See Parameter Index tables for
Block types in Section 5.
BLOCK NUMBER
Select from LCB Printout
TABLE FIELD*
1 = Function Block Configuration Parameters (Static)
2 = Function Block I/O Parameters (Dynamic)
* Configuration Parameters (static) and
I/O parameters (dynamic) cannot be accessed
in the same message since both the Static parameters
and the Dynamic parameters each start at Index Number 0.
Data Data Data
DATA FIELD
Four Bytes of data (32-bit IEEE Floating Point)
for each value returned (See Subsection 4.6)
. . .
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