Liberty 100 Smart Electricity Meter Technical Reference Manual
o Rate price (maximum 4 rates)
o Block (slab) threshold - maximum 3 blocks [(monthly (30 days), bi-monthly (61 days), quarterly
(91 days), half-yearly (182 days) and yearly (365 days)].
o Block threshold in 1 kWh resolution
o Tariff resolution period (block period or daily)
o Block period activation (calendar month reference is 1
st
January or the tariff activation date)
o Standing Charges
o Activation of tariff (immediate or delayed on respective date midnight)
e) Retain Credit UTRN: used for retaining credit in a meter after a refund and contains information such as
the date and time of the transaction, refund amount, transaction source, the new account balance,
currency and encrypted transaction code.
UTRNs can be uploaded to the meter via the WAN Interface, entered and sent over the HAN from an IHD or
entered using the meter’s keypad.
The meter will reject UTRNs if they fail authentication and are invalid. Each time a UTRN is rejected the meter
displays a failure message along with a failure reason such as ‘invalid UTRN’, ‘UTRN already processed’,
‘incorrect format’, etc. The date and time of transaction, the transaction source, transaction number, UTRN type
and the result code of the transaction are stored for each rejected UTRN.
Validation and authentication of remote top-up commands include verification of the meter operating mode,
command source and whether the UTRN has already been processed before or has a correct format. Failure to
validate or authenticate a UTRN will result in the meter sending a rejection alert.
Instructions for entering UTRNs can be found in Section 7.3 (Credit Mode) and Section 7.6 (Prepayment Mode).
When entering a UTRN via the meter’s keypad, there is a timeout period of 20 seconds after which time, if no
key has been pressed the meter will begin automatic authentication of the UTRN. During UTRN entry via the
meter’s keypad, key ‘A’ can be used to delete the last entered digits.
The meter allows five (5) successive incorrect UTRN entries after which it locks key ‘A’ (key ‘A’ is used for
initiating UTRN entry) for 30 seconds with a ‘KEY LOCKED’ message on its display as shown below.
Thereafter, the lock period doubles with each incorrect UTRN until the 10
th
attempt is reached when the lock
period is 16 minutes. Acceptance of a correct UTRN resets the incorrect UTRN counter and the lock period to
zero and takes necessary action based on the UTRN type.
UTRN attack message :
The meter keeps a record of the last 100 accepted and rejected UTRNs. The retailer can configure to send
alerts to HES for each success or failure with a snapshot of the meter status at the time of the update, before
and after the UTRN was accepted.
5.7 Meter Mode Changing Operation
Liberty 100 supports local and remote runtime switching of its operating modes via the engineering service
UTRN or on receipt of an authenticated command. It can be configured either with immediate effect or for a
future date. Switch mode requests for future dates can be cancelled remotely by authorised users. If power is off
during the scheduled date and time, the switchover will occur when power is restored.
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