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7.2.2 Manipulation recognition
For protection against manipulation attempts the ITZ has a manipulation recognition
system. There are two different types of recognition:
a) Terminal cover monitoring
b) Magnetic field monitoring
General
If the ITZ meter is in the parameter status then the manipulation monitoring is
„Offline“, that means no manipulations are registered. However, by pressing the
manipulation button or by applying an external magnetic field the manipulation
display („hand symbol“ in the display) can be tested.
Activation of the manipulation monitoring takes place thirty minutes after switching
off the parameter status.
Manipulation event
a) Terminal cover monitoring
If the ITZ is in normal operation then every attempt to open the terminal cover is
registered with the date and time. If the meter has a buffer battery the registration
can also take place in a no-voltage condition. A manipulation of the terminal cover is
signalised by a „hand symbol“ in the display. Furthermore via an output an alarm can
be activated.
The ITZ meter registers the numbers of opening of the terminal cover in the register
C.51.7(). With every further attempt to open the cover the increases by 1. The
register has 8 digits from 00000000 to 99999999.
For each billing period the manipulation attempts in the registers C.51.5() and
C.51.6() are saved. In these registers the last 10 manipulation attempts are saved. In
the register C.51.5() the start of the last manipulation attempt of the billing period is
saved with information about date and time. The register C.51.6() saves the end of
the manipulation attempt also with date and time.
b) Magnetic field monitoring
If the meter is in the normal operation mode then every attempt to manipulate the
meter with a magnetic field is registered with the date and time. A manipulation
attempt of this type is signalised by a „hand signal“ in the display.
The ITZ registers the number of these manipulation attempts in the register C.52.7().
With every further manipulation attempt the register is increased by 1.
The register has 8 digits from 00000000 to 99999999.
For each billing period the manipulation attempts are saved in the registers C.52.5()
and C.52.6(). In these registers the last 10 manipulation attempts are saved. In the
register C.52.5() the start of the last manipulation attempt of the billing period is
saved with the date and time. The register C.52.6() saves the end of the last
manipulation attempt also with the date and time. Furthermore via an output an
alarm can be activated.
