Split Single Phase DIN PLC Meter

The Sienna SSP DIN-R PLC meter is a 4-terminal bottom connect 80A DIN rail mounted Class1 split single phase pre-payment meter. It employs OFDM (Orthogonal Frequency Division Multiplexing) PLC technology between the MCU (Metering Control Unit) and the CIU (Customer Interface Unit).

The meter is rated at 230V (80A) with an operating temperature range of -15°C to +55°C with Class 1 active energy accuracy. The terminal arrangement is bottom connect and the IP rating of the meter is IP54.

The meter is configurable for either STS pre-payment or post-payment operation. It incorporates a tamper detection and disconnection feature. Communication with the meter is via an IEC62055-52 protocol optical port, however provision has been made to extend the communication options in the future to allow for back-end system communication.

The split metering configuration allows for revenue protection by separating the meter, that is securely installed in a metering enclosure, from the CIU that is on the customer premises. In the case of the CIU (common base with relay), a further level of bypass detection is achieved.


The MCU consists of the metering control elements: metrology circuits; STS token decryption and load monitoring with respective disconnecting and reconnecting actions. The IEC62055-52 optical interface is used for 2-way communication such as data extraction and STS token transfer.

Bi-colour LED status indicators are used to identify various meter states such as the relay state, tamper mode and communication status, adding a further level of troubleshooting without requiring access to the customer premises.


The CIU serves as the customer interface to the meter. The large LCD display has language independent icons indicating the meter status. A low credit threshold function notifies the user of a low credit condition by audible alarm and indication on the LCD. The keypad incorporates braille features for the partially sighted.

Customer focussed short codes are available to assist managing power consumption by, for example, displaying total kWh consumed or the instantaneous power.


  • OFDM PLC technology provides resilient high reliability communications in noisy electrical environments
  • Pre-payment and post-payment operating modes are available.
  • Bottom connect terminal arrangement for ease of installation.
  • Provision for different communication technology, with ESKOM DSP34-1635 QUSB port currently available.
  • Bi-colour LEDs to easily identify the meter status.
  • Quality of supply Over and Under states for voltage, frequency and power monitored.


IEC 62055-21       Electricity metering – Payment systems – Part 21 : Framework for standardization
IEC 62055-31       Particular Requirements - Static Payment Meters for active energy (Classes 1 and 2)
IEC 62055-41       Part 41 : Standard Transfer Specification (STS) – Application Layer protocol for one-way token carrier systems
IEC 62055-51       Part 51 : Standard Transfer Specification (STS) – Physical Layer Protocol one-way numeric and magnetic card token carriers
IEC 62055-52       Part 52 : Standard Transfer Specification (STS) – Physical Layer Protocol for a two-way virtual token carrier for direct local connection
SANS 1524-1       SANS Electricity Payment Systems – Part 1 : Payment meters
DSP 34-1635        ESKOM – Particular Requirements for Pre-payment meters
240-76619489     ESKOM – ALT Testing
IEC 62052-11       General Requirements, tests and test conditions –– Part 11 : Metering Equipment
IEC 62053-52       Electricity Metering Equipment (AC) –– Part 52 : Symbols


Voltage Range Un = 220V / 230V / 240V, 50Hz

(80% Un to 115% Un)

Frequency 50Hz +/- 2%
Current range Ib=5A, Imax = 80A
Accuracy Active Energy Class 1
Power supply and consumption Power consumption with CU connected in the voltage circuit of the meter is less than 2W and 10VA.
Rate Indicator 1000 imp/kWh
Temperature Operating Range -15°C to +55°C
Humidity Operating Range <95% RH
Protection Class (MCU) IP 54
RF Immunity 30V/m
Terminal Arrangements 4 Terminal bottom connect
Terminals Current rating 100A (continuous).

Conductor diameter 8mm or 35mm2

Sealing Meter enclosure sealed for life with terminal seal provision.
Metering Modes STS pre- and post-payment
Disconnections Zero Credit, Tamper, Reverse Energy, Over and Under Voltage, Over and Under Frequency, Over Power Limit
Tamper Magnetic, Relay CIU bypass, Reverse Energy Detection
Communication Option Optical port (IEC62055-52), PLC
Visual Indicators Rate, Relay Status, CIU Communication Status LEDs, LCD with language independent icons
Weight 390g
Dimensions (WxDxH) 55.9 x 110 x 105.5mm
Product Reliability Designed for a 15yr lifespan in the field


User Display LCD to 8 digits values & language independent icons
User Interface CIU keypad incorporating braille features
IP Rating Relay CIU   IP52

Standalone CIU   IP52

CIU Common Base (with relay) Relay rated to carry 80A 277VAC
CIU Standalone (with battery backup) Batteries accessible from the back of the unit with mains isolation safety feature


Pre- and post-payment Fully STS compliant


CIU (common base relay)

CIU (common base relay)2

CIU (standalone)