22/35
Released
Anti-tamper Features
© Gyr (Pty) Ltd
Cashpower Gemini HMI
– User Guide
8
Anti-tamper Features
8.1
General
The Gemini HMI electronic circuitry is mechanically sealed at the time of manufacture by screw
sealing plugs. The use of these sealing plugs ensures that there are visible signs of tampering if
unauthorised entry to the meter is attempted
On installation, the Gemini HMI terminal cover is fitted to the meter with a single terminal cover screw.
The screw is then sealed with utility-sealed wire seals. The use of the utility seal ensures that there is
a visible sign of tampering from the front of the meter.
8.2
Anti-Tamper Switch
The Gemini HMI meter is fitted with a mechanical anti-tamper facility fitted.
The tamper facility automatically detects if the meter terminal cover is removed. This condition will set
the tamper state thereby causing the meter to disconnect power to the household
– it will remain in the
tampered state when the cover is re-fitted to the meter
The tamper detect function may be enabled or disabled during production, or by means of a Set
Options Register token. The tampered condition may be monitored by using the information functions
8.3
Reverse Energy Detection
The meter includes a Significant Reverse Energy (SRE) detection feature. If the line and load wires
are swapped during installation, the meter will continue to operate and decrement credit, however, the
meter can be factory-programmed to tamper and disconnect the load should SRE be detected. The
reverse energy condition may be monitored by using the information functions
8.4
Resetting a Tamper Condition
Before resetting a tamper condition, care must be taken to remove the cause of the condition, e.g.
ensure that the meter is wired correctly and that the terminal cover is securely fitted to the meter and
that the tamper switch is closed. Failing to do this will cause an immediate tamper condition.
Once the terminal cover is fitted to the meter, check that the tamper switch is fully depressed by
checking the tamper switch status in the meter state registers. If a meter has been tampered, normal
operation can only be restored by entering a clear tamper token.
