STEVAL-IPE012V1 STMicroelectronics, STEVAL-IPE012V1 Datasheet - Page 20

• 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

Theory of operation
7.7
Table 8.
7.8
7.9
20/51
Load monitoring
The STPM10 includes a no-load condition detection circuit with adjustable threshold. This
circuit monitors the voltage and the current channels and, when the measured voltage is
below the set threshold, the internal signal BIL becomes high. Information about this signal
is also available in the status bit BIL.
The no-load condition occurs when the product of the VRMS and IRMS register values is
below a given value. This value can be set with the LTCH configuration bits. Four different
no-load threshold values can be chosen according to the two configuration bits LTCH (see
Table
When a no-load condition occurs (BIL=1) the integration of power is suspended and the
tamper module is disabled. The BIL signal can be accessed only through the SPI interface.
No-load detection thresholds
Error detection
In addition to the no-load condition and the line frequency band, the integration of power can
also be suspended due to an error detected on the source signals.
There are two kinds of error-detection circuits involved. The first checks all the Σ Δ signals
from the analog part if any is stacked at 1 or 0 within the 1/128 of f
In case of a detected error, the corresponding Σ Δ signal is replaced with an idle Σ Δ signal,
which represents a constant value of 0. All error and other resolved flags are treated as bits
of a device status and can be read out by means of the SPI interface.
Another error condition occurs if LED pin output signals are different from the internal
signals that drive them. This can occur if some of these pins are forced to GND or to some
other imposed voltage value. In this case, the internal status bit PIN is activated, providing
the information that some hardware problem has been detected.
Tamper detection module
The STPM10 is able to measure the current in both live and neutral wire with a time domain
multiplexing approach on a unique sigma delta modulator. This mechanism is adopted to
implement anti-tamper function. If this function is selected (see
wire currents are monitored; when the difference between the two measurements exceeds a
rated threshold the STPM10 enters the "tamper state", while in "normal state" the two
measurements are below the threshold.
In particular, both channels are not observed all the time, rather a time multiplex mechanism
is used. During the observation time of each channel, its active energy is calculated. A
tamper condition occurs when the absolute value of the difference between the two active
8).
LTCH
0
1
2
3
Doc ID 17728 Rev 3
K
1600
3200
6400
Table
800
LTCH
CLK
7), the live and neutral
period of observation.
STPM10