LTC2992: Dual Wide Range Power Monitor. More...

Files
file	LTC2992.cpp
	Header for LTC2992: Dual Wide Range Power Monitor.

file	LTC2992.h
	LTC2992: Dual Wide Range Power Monitor.

file	DC2561.ino
	LTC2992: Dual Wide Range Power Monitor.

Detailed Description

LTC2992: Dual Wide Range Power Monitor.

The LTC®2992 is a rail-to-rail system monitor that measures
current, voltage, power, charge and energy. It features an
operating range of 2.7V to 100V and includes a shunt regulator
for supplies above 100V. The current measurement common mode
range of 0V to 100V is independent of the input supply.
A 12-bit ADC measures load current, input voltage and an
auxiliary external voltage. Load current and internally
calculated power are integrated over an external clock or
crystal or internal oscillator time base for charge and energy.
An accurate time base allows the LTC2992 to provide measurement
accuracy of better than ±0.6% for charge and ±1% for power and
energy. Minimum and maximum values are stored and an overrange
alert with programmable thresholds minimizes the need for software
polling. Data is reported via a standard I2C interface.
Shutdown mode reduces power consumption to 15uA.


I2C DATA FORMAT (MSB FIRST):

Data Out:
Byte #1                                    Byte #2                     Byte #3

START  SA6 SA5 SA4 SA3 SA2 SA1 SA0 W SACK  X  X C5 C4 C3 C2 C1 C0 SACK D7 D6 D5 D4 D3 D2 D1 D0 SACK  STOP

Data In:
Byte #1                                    Byte #2                                    Byte #3

START  SA6 SA5 SA4 SA3 SA2 SA1 SA0 W SACK  X  X  C5 C4 C3 C2 C1 C0 SACK  Repeat Start SA6 SA5 SA4 SA3 SA2 SA1 SA0 R SACK

Byte #4                                   Byte #5
MSB                                       LSB
D15 D14  D13  D12  D11  D10  D9 D8 MACK   D7 D6 D5 D4 D3  D2  D1  D0  MNACK  STOP

START       : I2C Start
Repeat Start: I2c Repeat Start
STOP        : I2C Stop
SAx         : I2C Address
SACK        : I2C Slave Generated Acknowledge (Active Low)
MACK        : I2C Master Generated Acknowledge (Active Low)
MNACK       : I2c Master Generated Not Acknowledge
W           : I2C Write (0)
R           : I2C Read  (1)
Cx          : Command Code
Dx          : Data Bits
X           : Don't care



Example Code:

Read power, current and voltage

    CTRLA = LTC2992_CHANNEL_CONFIG_V_C_3|LTC2992_SENSE_PLUS|LTC2992_OFFSET_CAL_EVERY|LTC2992_ADIN_GND;  //! Set Control A register to default value in continuous mode
    ack |= LTC2992_write(LTC2992_I2C_ADDRESS, LTC2992_CTRLA_REG, CTRLA);   //! Sets the LTC2992 to continuous mode

    resistor = .02; // Resistor Value On Demo Board

    ack |= LTC2992_read_24_bits(LTC2992_I2C_ADDRESS, LTC2992_POWER_MSB2_REG, &power_code);  // Reads the ADC registers that contains V^2
    power = LTC2992_code_to_power(power_code, resistor, LTC2992_Power_lsb); // Calculates power from power code, resistor value and power lsb

    ack |= LTC2992_read_12_bits(LTC2992_I2C_ADDRESS, LTC2992_DELTA_SENSE_MSB_REG, &current_code); // Reads the voltage code across sense resistor
    current = LTC2992_code_to_current(current_code, resistor, LTC2992_DELTA_SENSE_lsb); // Calculates current from current code, resistor value and current lsb

    ack |= LTC2992_read_12_bits(LTC2992_I2C_ADDRESS, LTC2992_SENSE_MSB_REG, &SENSE_code);   // Reads SENSE voltage code
    SENSE = LTC2992_SENSE_code_to_voltage(SENSE_code, LTC2992_SENSE_lsb);  // Calculates SENSE voltage from SENSE code and lsb

    ack |= LTC2992_read_32_bits(LTC2992_I2C_ADDRESS, LTC2992_ENERGY_MSB3_REG, &energy_code);  // Reads energy code
  energy = LTC2992_code_to_energy(energy_code,resistor,LTC2992_Power_lsb, LTC2992_INTERNAL_TIME_lsb); //Calculates Energy in Joules from energy_code, resistor, power lsb and time lsb

  ack |= LTC2992_read_32_bits(LTC2992_I2C_ADDRESS, LTC2992_CHARGE_MSB3_REG, &charge_code);  // Reads charge code
    charge = LTC2992_code_to_coulombs(charge_code,resistor,LTC2992_DELTA_SENSE_lsb, LTC2992_INTERNAL_TIME_lsb); //Calculates charge in coulombs from charge_code, resistor, current lsb and time lsb

http://www.linear.com/product/LTC2992

http://www.linear.com/product/LTC2992#demoboards

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Use of the software either in source or binary form, must be run on or directly connected to an Analog Devices Inc. component.

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Detailed Description