Datasheet

Theory of operation STPM10
30/53 Doc ID 17728 Rev 4
Each configuration bit can be written by sending a byte command to STPM10 through its
SPI interface. The procedure to write the configuration bits is described in Section 7.19: SPI
interface.
Table 11. Configuration bit map
Address
Name
n. of
bits
Description
(1)
6-bit
binary
DEC
000000 0 - 1 Reserved
000001 1 MDIV 1
Measurement frequency range selection:
- MDIV=0: 4.000 MHz to 4.194 MHz
- MDIV=1: 8.000 MHz to 8.192 MHz
000010 2 RC 1
Type of internal oscillator selection:
- RC=0:crystal oscillator,
- RC=1:RC oscillator
000011 3 - 1 Reserved
000100 4 - 1 Reserved
000101 5 PST 1
Current channel sensor type and gain:
If TMP=0
PST=0: primary is CT x8, secondary is not used, no tamper
PST=1: primary is shunt x32, secondary is not used, no tamper
If TMP=1
PST=0: primary is CT x8, secondary is CT x8, tamper
PST=1: primary is CT x8, secondary is shunt x32, tamper
000110 6 - 1 Reserved
000111 7 TMP 1 Tamper enable
001000 8 FRS 1
Power calculation when BFR=1
- FRS=0: energy accumulation is frozen, power is set to zero;
- FRS=1: normal energy accumulation and power computation (p=u*i);
001001 9 MSBF 1
Bit sequence output during record data reading selection:
- MSBF=0: MSB first
- MSBF=1: LSB first
001010 10 FUND 1
This bit swaps the information stored in the type0 (first 20 bits of DAP register)
and type1 (first 20 bits of DFP register) active energy.
- FUND = 0: type 0 contains wide-band active energy, type1 contains
fundamental active energy
- FUND = 1: type 0 contains fundamental active energy, type1 contains wide-
band active energy
001100 12
LTCH 2
No-load condition threshold as product between V
RMS
and I
RMS
:
LTCH=0 800
LTCH=1 1600
LTCH=2 3200
LTCH=3 6400
001101 13
(1)