Using The Data Log Wizard - Siemens SIMATIC S7-200 System Manual

Using the Data Log Wizard

Use the Data Log Wizard to configure up to four data logs. The Data Log Wizard is used to:
Define the format of the data log record
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Select data log options such as time stamp, date stamp, and clear data log on upload
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Data Log
Specify the maximum number of records that can be stored in the data log
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Create project code used to store records in the data log.
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The Data Log Wizard creates a data log configuration that includes the following:
A symbol table for each data log configuration. Each table includes symbol names that are
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the same as the data log field names. Each symbol defines the V memory addresses
needed to store the current data log. Each table also includes a symbolic constant to
reference each data log.
A data block tab for each data log record that assigns V memory addresses for each data
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log field. Your program uses these V memory addresses to accumulate the current log data
set.
A DATx_WRITE subroutine. This instruction copies the specified data log record from V
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memory to the memory cartridge. Each execution of DATx_WRITE adds a new data record
to the log data stored in the memory cartridge.
Data Log Options
You can configure the following optional behaviors for the data log. See Figure 14-2.
Time Stamp
You can include a Time Stamp with each
data log record. When selected, the CPU
automatically includes a time stamp with
each record when the user program
commands a data log write.
Date Stamp
You can add a Date Stamp to each data
log record. When selected, the CPU
automatically includes a date stamp with
each record when the user program
commands a data log write.
Clear Data Log
Clear Data Log -- You can clear all
records from the data log whenever it is
uploaded. If you set the Clear Data Log uploaded. If you set the Clear Data Log
option, the data log will be cleared each
time it is uploaded.
Data logs are implemented as a circular queue (when the log is full, a new record replaces the
oldest record). You must specify the maximum number of records to store in the data log. The
maximum number of records allowed in a data log is 65,535. The default value for the number of
records is 1000.
Using Data Logs
Figure 14-2 Data Log Options
Chapter 14
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