Data Protection - RMG EC 900 Operating Instructions Manual

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Data protection

The program of the EC 900 is protected by a checksum. The checksum of the program version can
be read under "CS displd" in the "TYPE" book. On the same screen, the user can initiate a manual
check of the checksum via "Calc CS" mode.
Parameters are stored twice and are compared with each other continuously. Another copy of the
parameters is saved in an F-RAM. When a parameter is changed, the new value will be directly
saved in the F-RAM. When a comparison error has been detected, a fault message will be generat-
ed.
Totalizers are stored three times and are compared with each other and also saved continuously in
the F-RAM. When a comparison error has been detected, a fault message will be generated.
In the case of devices with an internal or external communication unit, there is a continuous data
exchange between the main unit (MU) and the communication unit (CU). All parameters, measured
values and archive entries are transferred to the communication unit.
A password is absolutely necessary to read or write via one of the various interfaces. However, in
order to read data, entering the password may be disabled. If the user tries to change a parameter
of the main unit through one of the interfaces, it will first be checked whether the password re-
quired for the relevant parameter has been transmitted. Then it will be checked whether the new
value is within the permissible limits before it is stored in the appropriate memory. The transmis-
sion of the password together with its source, date and time will be stored in an archive. This also
applies for the parameter to be changed which is recorded at least in one of the logbooks.
Each data record in the various archives has its own checksum (CRC). If the archives are read via a
PC program, the program reading the data must be able to generate this checksum on its own and
compare it with the checksum transferred. If an error is detected, the PC program will have to gen-
erate a fault message.
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CONSTRUCTION AND FUNCTION
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