SGM-D4

Product information

The SGM D4 is a sturdy device with the following features: 

• Housing according to FNN specification for three-point mounting with top-hat rail for integration of additional devices 
• Flexible measurement via shunts with intrinsic immunity to harmonics and external magnetic fields: +A (consumption meter) or -A (supply meter), +A/-A (bidirectional meter) or totalizing supply meter 
• LMN-485 bus interface for remote communication with TLS security according to BSI-TR-03116-3 
• PIN protection for extended data display and data output 
• Front optical interface for local data provision (INFO interface) 
• LCD according to FNN specification for display of metrological and historical data over two years,  two lines with special symbols  
• Output of grid status data 
• Single-tariff or dual-tariff version with external control via accessory terminals as an option 

Standard functions

In accordance with statutory provisions, the meter acts as a reliable and secure metering device for acquisition of billing-related active power quantities and grid-friendly measurement data and parameters, such as effective values of line voltage and current, power, phase angle and line frequency. 

Active power is measured in both directions, with the following measurement modes being available: 

• Unidirectional meter (+A or -A)
• Bidirectional meter (+A and -A)
• Supply meter, totalizing without reverse running lock (-A) 

The current sensors used are sturdily mounted, precise shunts, which also optionally enable Class b accuracy. The actual power values in all the phases are registered internally and are available over the data interfaces. Actual power values on all lines are logged internally and available over the data interfaces. The measurement mode is set at the factory in accordance with metrological requirements. 

The meter also provides the following grid status data (grid functions): 

• Active power (total active power P as well as individual phase values P_L1, P_L2, P_L3) calculated as average values over 1 second, resolution 0.1 W 
• Effective values of line voltages U_L1, U_L2, U_L3 calculated as average values over 1 second, accuracy 1% of measured value, resolution 0.1 V 
• Effective values of line currents I_L1, I_L2, I_L3 calculated as average values over 1 second, resolution 0.1 A, accuracy 1% of measurement 
• Phase angles φ_L1, φ_L2, φ_L3, accuracy/resolution 1° relative to the fundamental frequency 
• Phase angle between external line voltages U2/U1 and U3/U1 
• Line frequency f_line, accuracy 1%, resolution 0.1 Hz 

The daily, weekly, monthly and annual values of active power over a period of two years are recorded in the ring buffer as historical data and displayed under PIN protection. The front optical interface is used for local provision of measurement data and device information according to SML/COSEM at 1-second intervals. This function is also PIN protected. The PIN entry is made via the optical button. 

The LMN bidirectional RS-485 interface serves for system communication with an SMGW at a baud rate of 921.6 kbit/s.  The protocols used are HDLC in the connection layer and SML/COSEM in the application layer. In the “smart metering system” variant communication is TLS-secured in accordance with BSI TR 03116-3.

Optional Functions

As an option, the dual-tariff function with external control is available via terminals 13 and 15. The tariff registers in both power directions, as well as the current tariff, are shown on the display. This function and the display of historical data are disabled by the gateway in the smart metering system variant. Other functions such as tariffing, measurement data recording and control operations are basically assigned to the secure gateway or the respective control device. 

Removing the terminal cover or attempted influence using magnets is detected as manipulation and recorded as such.