Technical data

Memory usage and application examples
3.2 Memory usage for data logging
Structure and Use of the CPU Memory
Function Manual, 01/2013, A5E03461664-01
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Network 6
A rising edge at the REQ input of the instruction "DataLogOpen" simulates the user pressing
a button on an HMI device which opens a Data Log. If you open a Data Log in which all data
records have been allocated process data, the next execution of the "DataLogWrite"
instruction will overwrite the oldest data record. You can, however, also retain the old
Data Log and instead create a new Data Log. This is shown in network 7.
Figure 3-10 Network 6
Network 7
The ID parameter is an IN/OUT type. First, you enter the ID value of the existing Data Log
whose structure you want to copy. Once the "DataLogNewFile" instruction has been
executed, a new and unique ID value for the new Data Log will be written back to the
address of the ID reference. The required detection DONE bit = TRUE is not shown. An
example for the logic of the DONE bit can be found in networks 1, 2 and 4.
Figure 3-11 Network 7