Application description

AN3157

4/26

Doc ID 17105 Rev 1

1

Application description

The purpose of this STEVAL-IPE010V1 demonstration kit is to provide an evaluation

platform for the STPMC1 and STPMS1 devices, but it can also be used as a starting point to

design a Class 1 meter for 2 to 4-wire power line systems using delta or wye service.

Each phase is monitored by an independent daughterboard, in which an autonomous power

supply is provided to the board itself and, once it is connected, also to the motherboard.

In this board, the STPMS1 device senses the phase current through a CT or a shunt sensor,

and the phase voltage through a voltage divider. The presence of dedicated networks

reduces greatly the sampling (aliasing) noise and the crosstalk noise between voltage and

current channels, increasing meter precision. The STPMS1 produces a sigma-delta stream,

sent together with the supply voltage, to the STPMC1 through a card edge connector.

The motherboard receives the sigma-delta streams from the daughterboards which are

further elaborated by the STPMC1. This device, from a 4.194 MHz crystal oscillator,

provides a common clock with programmable frequency to all the daughterboards.

The motherboard, through a 10-pin flat cable connector (P1 in Figure 2) can be interfaced to

a microprocessor board to implement advanced metering features (multi-tariff, data

management and storage, communication, etc). It also has stepper motor connectors for a

simple energy meter implementation (W2, W5 in Figure 2).

The STPMC1 board can also be connected to a dedicated GUI (graphical user interface)

through the STPMxx parallel programmer/reader released with the application.

1.1

Operating conditions

Table 1.

Operating conditions

Condition

Value

Unit

230

50 / 60 ± 10%

Hz

- 40 / + 85

°C