STEVAL-IPE012V1 STMicroelectronics, STEVAL-IPE012V1 Datasheet - Page 21

• Manufacturer Part Number: STEVAL-IPE012V1
• Description: EVAL BOARD ENERGY METER
• Manufacturer: STMicroelectronics
• Series: -r

Specifications of STEVAL-IPE012V1

• Design Resources: STEVAL-IPE012V1 Schematic STEVAL-IPE012V1 BOM
• Main Purpose: Power Management, Energy/Power Meter
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: STPM10BTR, STM8L152
• Primary Attributes: Single Phase with 1 Current Transformer & Shunt
• Secondary Attributes: Tamper Detection
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-11462

STPM10
7.9.1
Figure 18. Timings of tamper module - Primary channel selected
MUX
INH
Tamper power integrators
Cycles
energy values is greater than a certain percentage of the averaged energy during the
activated tamper module (see
This percentage value can be selected between two different values (12.5 % and 6.25 %)
according to the value of the configuration bit CRIT.
The tamper condition is detected when the following formula is satisfied:
Equation 1
EnergyCH1 - EnergyCH2 > K
where K
The detection threshold is much higher than the accuracy difference of the current channels,
which should be less than 0.2 %, but, some headroom should be left for possible transition
effect, due to accidental synchronism of actual load current change with the rhythm of taking
the energy samples.
The tamper circuit works if the energies associated with the two current channels are both
positive or negative, if the two energies have different sign, the tamper is on all the time
however, the channel with the associated higher power is selected for the final computation
of energy.
When internal signals are not good enough to perform the calculations, i.e. line period is out
or range or ΔΣ signals from analog section are stacked at high or low logic level, or no load
condition is activated, the tamper module is disabled and its state is preset to normal.
Detailed operational description
The meter is initially set to normal state, i.e. tamper not detected.In this condition the
primary channel is selected for final integration of energy. In such state the values of both
load currents should not differ more than the accuracy difference of the channels does.
Sixty-four periods of line voltage is used as a tamper checking period.
After 24 periods of line voltage two internal signals MUX and INH are changed in order to
enable secondary current channel and to freeze the last power and RMS values of primary
current channel. The following 16 periods of line frequency are used for tamper detection
integration. During this gap, the final energy calculation does not use the signal from
selected channel but the frozen values.
Four line periods after the INH switch, the integration of power from secondary current
channel is started and lasts four periods. Additional four line periods later MUX signal is
switched back to primary current channel and the integration for tamper detection is started.
The timings of MUX and INH signals are shown in
CRIT
Ch 1
24
can be 12.5 % or 6.25 %.
CRIT
Doc ID 17728 Rev 3
Equation
4
Ch 2
(EnergyCH1 + EnergyCH2)/2;
B
4
1).
4
Ch 1
A
4
Figure 18
below.
24
Ch 1
Theory of operation
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