Kuhnke Electronics Instruction Manual

4.8 Extraremanent Data
4.8.1 Remanence Compliant to IEC 11631-3
117
Remanent Data
Retain variables are re-initialised when a program has
been transferred (i.e. they are set =0 unless another initial
value has been defined).
(Since all data references in the newly loaded program
may have changed, it would be the safest approach to
simply clear all Retain data.)
IEC 11631-3 rules that persistent data are re-initialised
following a reset.
If Retain and Persistent data are combined, a reset (cold)
or (origin) re-initialises the data.
This approach allows important operative data or recipes
to be safely stored at the commissioning and startup
stage.
The CoDeSys runtime system of PCControl 645-12M-PCI
and the Ventura SlotPLC does not support variable
property "PERSISTENT".
Property of variables "Retain" is not available for
variables with fixed addresses (%IB, %QB, %MB …)