71m6515h Maxim Integrated Products, Inc., 71m6515h Datasheet - Page 39

• Manufacturer Part Number: 71m6515h
• Description: 71m6515h Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

Registers Controlling Temperature Measurement and Compensation
DEG_SCALE (0x1C)
FREQ_DELTA_T (0x11)
TEMP_NOM (0x13)
TEMP_RAW (0x12)
PPMC1_2 (0x1B)
Page: 39 of 57
This register holds the scale factor used to calculate the internal temperature value provided by the temperature sensor to
temperature in degrees Celsius (°C). The default value is 22721 and should not be changed.
This register holds frequency and temperature information in two bytes each.
31
FREQUENCY (see Output Registers)
Bits 15-0: These bits (DELTA_T) represent the temperature information relative to the value stored in the TEMP_NOM
register. One LSB is equivalent to 0.1°C. The formula used for DELTA_T is:
This register holds the nominal (reference) temperature. During calibration, the host must write the value read from
TEMP_RAW to TEMP_NOM in order to enable temperature compensation. See the Meter Calibration section for details. The
temperature available in register DELTA_T is based on the difference between the current temperature, as provided in
TEMP_RAW, and the reference temperature provided by TEMP_NOM.
This read-only register holds the raw temperature provided by the temperature sensor on the 71M6515H chip. During
calibration, the host must write the value read from TEMP_RAW to TEMP_NOM in order to enable temperature
compensation.
This register holds the linear and squared compensation factors for the ADC temperature compensation. The allowed
range is (2
31
PPMC = ADC linear factor (PPMC = 26.84 * PPM/°C )
Changes to PPMC1_2 by the host are only allowed if the DEFAULT_PPM bit in the CONFIG register is zero. If additional
temperature compensation by the host, e.g. for external components, is required, the procedure is as follows:
1)
2)
The host sets the DEFAULT_PPM bit in the CONFIG register to 1 and then reads PPMC and PPMC2.
register to 0 and then writes the modified values to PPMC and PPMC2.
The host then adds the compensation factors to PPMC and PPMC2, resets the DEFAULT_PPM bit in the CONFIG
DELTA_T = -DEGSCALE*2
Example: At calibration time, the raw temperature value of 853030 was read from the TEMP_RAW register and
15
calculates the temperature difference to:
This value is interpreted as +4.4°C.
written to the TEMP_NOM register. At a later time, the raw temperature register reads 844866. The 71M6515H
– 1) to – (2
DELTA_T = -DEGSCALE*2
15
– 1). Both words are reset to zero if TEMP_NOM equals zero.
-22
*(TEMP_RAW-TEMP_NOM)
© 2005-2008 TERIDIAN Semiconductor Corporation
-22
*(TEMP_RAW-TEMP_NOM) = 44
16
16
15
DELTA_T
15
PPMC2 = ADC quadratic factor (PPMC2 = 1374 * PPM/°C
Energy Meter IC
DATA SHEET
71M6515H
MARCH 2008
V1.4
0
0
2
)