Saia-Burgess Controls AG
User Manual Standby System │ Document 27-645 │ Edition ENG 02 │ 2017-04-26
Media Exchange
Diagnostic
2-10
2
NOTES
Indexed Addressing
The media addresses of the synchronization data are taken from the addresses actually
used by the program. If media are accessed using the Index Register, these addresses
may not be taken into account if they are at the end of the address range. If the Index
Register is used, always ensure that the indexed addresses are within the ranges shown
at or beyond the end of the indexed range, to ensure the indexed media are also trans-
ferred.
Absolute addresses are recommended
It is recommended to use sequential absolute addresses (e.g. R 1000, R 1001, R 1002
...) for media exchange symbols instead of dynamic addresses, so the addresses will
never change when a build is done. The data to be transferred are treated as an array
instead of an array are transferred, and there may be alignment problems which require
a “Device / Advanced > Clean Files - Symbol Information Files” operation. If there is an
alignment problem, you will receive the “Redundancy media exchange dynamic address-
es are incompatible” error (see below).
Error 939: Standby system media exchange dynamic addresses are incompatible
(ToRed/FromRed)
You may see this build error if you have used dynamic addresses for the media ex-
be transferred into arrays, to reduce the number of transfers. With dynamic addresses,
addresses in one CPU may be consecutive, and in the other they may be separate. This
means that the optimized arrays will not be the same, and the data cannot be trans-
ferred. The solution is to do the “Device / Advanced > Clean Files - Symbol Information
Files” operation, or to edit the symbols to use consecutive absolute addresses.
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