Rockwell Automation 9301 Series RSView32 Users Guide - Manual (Page 237)

Configuring data logging
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all tags, whether their values have changed or not, making the wide
format inefficient.
1. Click On Change.
2. In the Change Percentage field, type the percent the tag value has
to change in order to trigger logging. You can type a decimal value,
if desired.
The percentage is based on the tag’s minimum and maximum
values as configured in the Tag Database editor. Only the tags that
change by the specified percentage are logged. Zero means all
changes are logged.
3. In the Heartbeat field, type a time, and then click a time unit to
specify how often tag values will be logged even if no change has
occurred. If you do not want to use the heartbeat, type 0.
The heartbeat ensures that the data in the log file is current. The
heartbeat is also a good way to ensure that data logging is working
and acquiring valid data.
Logging on demand
Logging on demand means that data is logged for a model only when
the DataLogSnapshot command is issued. When the
DataLogSnapshot command is executed, tag values for all tags in the
specified model or models are logged.
To log on demand:
1. Click On Demand.
2. Run the model or models for which data will be logged. To run a
model, select the model in the Startup editor or issue the
DataLogOn <file> command where file is the name of the data log
model.
3. Issue the DataLogSnapshot command, as described next.