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B.5.4.3: Log Retrieval Procedure
The following procedure documents how to retrieve a single log from the oldest record to the newest
record, using the "normal" record type (see Scope). All logs are retrieved using the same method. See
Section B.5.4.4 for a Log Retrieval example.
NOTES:
This example uses auto-increment.
In this example, Function Code 0x23 is not used
You will find referenced topics in Section B.5.3. Block Definitions.
Modbus Register numbers are listed in brackets.
1. Engage the Log:
a) Read the Log Status Block.
i.
Read the contents of the specific logs' status block [0xC737+, 16 reg] (see Log
Headers).
ii. Store the # of Records Used, the Record Size, and the Log Availability.
iii. If the Log Availability is not 0, stop Log Retrieval; this log is not available at this
time. If Log Availability is 0, proceed to step 1b (Engage the log).
This step is done to ensure that the log is available for retrieval, as well as retrieving
information for later use.
b) Engage the log.
Write log to engage to Log Number, 1 to Enable, and the desired mode to Scope (default
0 (Normal)) [0xC34F, 1 reg]. This is best done as a single-register write.
This step will latch the first (oldest) record to index 0, and lock the log so that only
this port can retrieve the log, until it is disengaged.
c) Verify the log is engaged.
Read the contents of the specific logs' status block [0xC737+, 16 reg] again to see if the
log is engaged for the current port (see Log Availability).
If the Log is not engaged for the current port, repeat step 1b (Engage the log).
d) Write the retrieval information.
i. Compute the number of records per window, as follows:
ii. Write the Records per window, the Number of repeats (1), and Record Index (0)
[0xC350, 3 reg].
This step tells the Shark
2. Retrieve the records:
a) Read the record index and window.
Read the record index, and the data window [0xC351, 125 reg].
NOTES:
E
Electro Industries/Gauge Tech
RecordsPerWindow = (246 \ RecordSize)
If using 0x23, set the repeat count to 2-8. Otherwise, set it to 1.
Since we are starting from the beginning for retrieval, the first record
index is 0.
®
200 meter what data to return in the window.
If the meter Returns a Slave Busy Exception, repeat the request.
If the Window Status is 0xFF, repeat the request.
If the Window Status is 0, go to step 2b (Verify record index).
We read the index and window in 1 request to minimize communication time,
and to ensure that the record index matches the data in the data window returned.
Doc# E149701
B-12
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