B.5.4.3: Log Retrieval Procedure - Electro Industries Shark 200 Installation & Operation Manual

NOTES:
• By itself this feature would not provide any advantage, as the same data will be
returned RC times. However, when used with auto-incrementing, this function con-
denses up to 8 requests into 1 request, which decreases communication time, as
fewer transactions are being made.
• Keep in mind that the contents of the response data is the block of data you
requested, repeated N times. For example, when retrieving log windows, you
normally request both the window index, and the window data. This means that the
first couple of bytes of every repeated block will contain the index of that
window.
• In the Shark® 200 meter repeat counts are limited to 8 times for Modbus RTU, and
4 times for Modbus ASCII.
The response for Function Code 0x23 is the same as for Function Code 0x03, with the
data blocks in sequence.
IMPORTANT! Before using function code 0x23, always check to see if the current
connection supports it. Some relay devices do not support user defined function
codes; if that is the case, the message will stall. Other devices don't support 8 repeat
counts.

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 B.5.4.4: Log Retrieval Example on page B-21.
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:
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B: Modbus Map and Retrieving Logs
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Doc E149701 B-18