- 您现在的位置：买卖IC网 > Sheet目录299 > 71M6543F-IGT/F (Maxim Integrated Products)IC ENERGY METERING
71M6543F/71M6543G Data Sheet
differential signal conditioning circuit, as shown in Figure 29 , to connect the CTs to the 71M6543. Current
transformers may also require temperature compensation. The copper wire winding in the CT has dc
resistance with a temperature coefficient, which makes the voltage delivered to the burden resistor
temperature dependent, and the burden resistor also has a temperature coefficient. Thus, each CT sensor
channel needs to compensate for the 71M6543 VREF, and optionally for the temperature dependency of the
CT and its burden resistor depending on the required accuracy class.
The MPU has the responsibility of computing the necessary sample gain compensation values required for
each sensor channel based on the sensed temperature. Maxim provides demonstration code that
implements the GAIN_ADJx compensation equation shown below. The resulting GAIN_ADJx values are
stored by the MPU in five CE RAM locations GAIN_ADJ0-GAIN_ADJ5 ( CE RAM 0x40-0x44 ). The
demonstration code thus provides a suitable implementation of temperature compensation, but other
methods are possible in MPU firmware by utilizing the on-chip temperature sensor while storing the sample
gain adjustment results in the CE RAM GAIN_ADJn storage locations. The demonstration code maintains
five separate sets of PPMC and PPMC2 coefficients and computes five separate GAIN_ADJn values
based on the sensed temperature using the equation below:
10 ? TEMP _ X ? PPMC 100 ? TEMP _ X 2 ? PPMC 2
GAIN _ ADJx = 16385 +
2 14 2 23
+
the sample in each corresponding sensor channel. A GAIN_ADJx value of 16,384 (i.e., 2 )corresponds to
In the above equation, TEMP_X is the deviation from nominal or calibration temperature expressed in
multiples of 0.1 °C. The 10x and 100x factors seen in the above equation are due to 0.1 C scaling of
The GAIN_ADJn values stored by the MPU in CE RAM are used by the CE to gain adjust (i.e., multiply)
14
unity gain, while values less than 16,384 attenuate the samples and values greater than 16,384 amplify
the samples.
o
TEMP_X . For example, if the calibration (reference) temperature is 22 °C and the measured temperature
is 27 °C, then 10* TEMP_X = (27-22) x 10 = 50 (decimal), which represents a +5 °C deviation from 22 °C.
In the demonstration code, TEMP_X is calculated in the MPU from the STEMP[10:0] temperature sensor
reading using the equation provided below and is scaled in 0.1°C units. See 2.5.5 71M6543 Temperature
Sensor on page 53 for the equation to calculate temperature in °C from the STEMP[10:0] reading.
Table 67 shows the five GAIN_ADJx equation output storage locations and the voltage or current
measurements for which they compensate.
Table 67: GAIN_ADJx Compensation Channels ( Figure 3 , Figure 32 , Table 2 )
Gain Adjustment Output
GAIN_ADJ0
GAIN_ADJ1
GAIN_ADJ2
GAIN_ADJ3
GAIN_ADJ4
CE RAM Address
0x40
0x41
0x42
0x43
0x44
Sensor Channel(s)
(pin names)
VADC8 (VA)
VADC9 (VB)
VADC10 (VC)
IADC0-IADC1
IADC2-IADC3
IADC4-IADC5
IADC6-IADC7
Compensation For:
VREF in 71M6543 and Voltage Divider
Resistors
VREF in 71M6543, CT and Burden
Resistor (Neutral Current)
VREF in 71M6543, CT and Burden
Resistor (Phase A)
VREF in 71M6543, CT and Burden
Resistor (Phase B)
VREF in 71M6543, CT and Burden
Resistor (Phase C)
determined by the values stored in the PPMC (1 order coefficient) and PPMC2 (2
order coefficient),
In the demonstration code, the shape of the temperature compensation second-order parabolic curve is
st nd
which are typically setup by the MPU at initialization time from values that are stored in EEPROM.
To disable temperature compensation in the demonstration code, PPMC and PPMC2 are both set to zero
for each of the five GAIN_ADJx channels. To enable temperature compensation, the PPMC and PPMC2
coefficients are set with values that match the expected VREF temperature variation and optionally the
v2
91
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
71M6545-IGT/F
IC ENERGY METERING
720-10007-00300
CBL D-SUB 9PIN FMAL-25PIN FML 3M
720-10010-00025
CBL DSUB 9PIN FML-25PIN MAL .25M
720-10020-00300
CBL DSUB 9PIN FML-9PIN MALE 3M
720-10021-00300
CBL DSUB 9PIN FML-9PIN FEMAL 3M
72231-0881
8 POS T/P SHLD 4 GR ASSY
7250B
PANEL KIT BOTTOM FOR R-1220 CASE
731-10061-00200
CBL DSUB HD 15FEMAL-15MALE 2.0M
相关代理商/技术参数
71M6543F-IGTR/F
功能描述:计量片上系统 - SoC Precision Energy Meter IC
RoHS:否 制造商:Maxim Integrated 核心:80515 MPU 处理器系列:71M6511 类型:Metering SoC 最大时钟频率:70 Hz 程序存储器大小:64 KB 数据 RAM 大小:7 KB 接口类型:UART 可编程输入/输出端数量:12 片上 ADC: 安装风格:SMD/SMT 封装 / 箱体:LQFP-64 封装:Reel
71M6543FT-IGT/F
制造商:Maxim Integrated Products 功能描述:ENERGY METER ICS - Rail/Tube
71M6543FT-IGTR/F
制造商:Maxim Integrated Products 功能描述:3-PHASE SOC, 64KB FLASH, PRES TEMP SENSOR - Tape and Reel
71M6543G
制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Selectable Gain of 1 or 8 for One Current Energy Meter ICs Metrology Compensation
71M6543GH
制造商:未知厂家 制造商全称:未知厂家 功能描述:电表IC
71M6543GHT-IGT/F
制造商:Maxim Integrated Products 功能描述:3-PHASE, 128KB, PRES TEMP SENSOR, HI PREC - Bulk
71M6543GHT-IGTR/F
制造商:Maxim Integrated Products 功能描述:3-PHASE, 128KB, PRES TEMP SENSOR, HI PREC - Tape and Reel
71M6543G-IGT/F
功能描述:计量片上系统 - SoC Precision Energy Meter IC RoHS:否 制造商:Maxim Integrated 核心:80515 MPU 处理器系列:71M6511 类型:Metering SoC 最大时钟频率:70 Hz 程序存储器大小:64 KB 数据 RAM 大小:7 KB 接口类型:UART 可编程输入/输出端数量:12 片上 ADC: 安装风格:SMD/SMT 封装 / 箱体:LQFP-64 封装:Reel