9.2 Retentiveness of Data
Data is retentive if it is automatically saved when the PLC is stopped or power cycled.
The following data is retentive:
• Program logic
• Fault tables and diagnostics
• Overrides
• Word data (%R, %AI, %AQ)
• Bit data (%I, %SC, %G, fault bits and reserved bits)
• Word data stored in %Q and %M
• Data in %Q or %M references that are used as function block outputs or with
retentive coils:
− -(M)- retentive coils
− -(/M)- negated retentive coils
− -(SM)- retentive SET coils
− -(RM)- retentive RESET coils
The last time a %Q or %M reference is used with a coil, the coil type determines
whether the data is retentive or non-retentive. For example, if %Q0001 was last
programmed as the reference of a retentive coil, the %Q0001 data is retentive.
However, if %Q0001 was last programmed on a non-retentive coil, then the %
Q0001 data is non-retentive.
• %Q or %M references that have been made retentive by specifically declaring them
to be retentive. %Q and %M references default to nonretentive.
The following data is non-retentive:
• The states of transition coils.
• %T data
• %S, %SA, and %SB data (but %SC bit data IS retentive)
• %Q and %M references that have not been declared to be retentive.
• %Q and %M references that are used with non-retentive coils:
− -( )- coils
− -(/)- negated coils
− -(S)- SET coils
− -(R)- RESET coils
116 GFK-1503E VersaMax PLC User Manual
For public disclosure
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