The Microcontroller Tool Kit (MTK) software from Maxim is available for free download. Click on the Calculate Phase Angle Compensation button to compute the correction value. Click on the Calculate Phase Angle Compensation button to compute the correction hex value. Erases the MAXQ3180 configuration information from the MAXQ2000's flash memory. The PC software for this reference design lets users recalibrate the reference meter for specific experiments. High 2 should be selected so that the input amplitude on the MAXQ3180's current input pins is close to, but higher than (VREF/2)/32 (0.032V). Select the hex file to load into the MAXQ2000. However, initialization is not required. Figure 9. Exercise extreme caution when making connections to a live system! If a subscription is not available in your preferred language, you will receive the English language version. Low 1 should be selected so that the input amplitude on the MAXQ3180's current input pins is close to, but lower than (VREF/2)/32. Maxim may periodically update the MAXQ2000 code to support improvements or new features. The "cold board" (the board that contains the microcontroller and display) is safe to touchno high voltages exist on this board. Click on the Read buttons to retrieve and display the current values measured by the meter. Select the desired serial port for the JTAG adaptor on the Options menu: Options, then Configure Serial Port. More detailed image (PDF, 241kB) Click Write to write the correction value to the X.PA0 register (X = A). Harmonics Pin 1 of the JTAG cable is normally on the edge of the cable marked by a red or pink color. Then click the Calculate Gain Factor button to compute the corresponding hex Gain register value. Note that the same PC software supports both the MAXQ3180 and the MAXQ3183. To exit stop mode one must initiate one of the following: The active-low RESET pin is not brought out to the cold board on the reference design, so viable options are A and C in the above list. The table below shows the difference between the reference-design meter (column H(k)/H(1)) and the tester measurement (Tester column). What project(s) will these Maxim parts be used in? Accuracy test results for some typical configurations are shown below. You must refresh this tab before proceeding. Clicking on the Read buttons will read the phase angles as seen by the meter. G is converted into a 16-bit unsigned integer before writing to the MAXQ3180 Gain register. When connecting the JTAG cable, make sure that pin 1 of the cable is connected with pin 1 of the JTAG header on the board. Please provide as much detail as possible in your answers. Figure 10. Status Be sure to power off the AC supply before proceeding. The MAXQ3180 supports phase-angle compensation in three load ranges: high, mid, and low. Figure 13. As an example, for each individual phase and the combined (total) of the three phases plus neutral, the software retrieves: the voltage and current RMS values, active power, reactive power, apparent power, fundamental power, harmonics, and power factors. CC value is saved to the MAXQ3183 TEMP_CC register if the target device is the MAXQ3183. Note that when evaluating the MAXQ3181 in the rather simplistic manner of the reference design, some metering parameters that are not available in the MAXQ3181 will appear random and meaningless. Note that you could apply the same gain factor value to all three voltage Gain registers to save calibration time if your input circuits are very consistent (i.e., would yield the same gain factor values). Virtual registers map Vector sum (MAXQ3183 only) If the Gain register is not initialized, the gain factor calculation needs to factor in the existing factor (GOLD). In LOWPM mode the MAXQ3180 runs on the internal 1MHz clock instead of the external high-frequency crystal; it only provides a subset of measurement parameters. For simplicity, this application note will refer to the target device simply as the MAXQ3180; the MAXQ3183 and its unique features will be cited only when necessary. Please contact customer support. You will receive an e-mail notification if you subscribe to Maxim EE-Mail. To use Automatic mode for gain calibration of any parameter (voltage, current, or power), the meter tester must provide the same input signal levels to all three input circuits of the meter. My Company Name The RMS measurements agree with the source values very well. However, some low-cost current transformers do exhibit significant phase dependency with respect to loading levels. Note that the user can directly enter a phase compensation value here too, in 2-byte wide and 2s complement hex format. Stay informed on the latest product developments, technical events and technology training. If you are using an AC supply, exercise extreme caution when attaching the JTAG cable to the meter or during program loading. Write value V to register at address RegAddr, where V is expressed in hex. PF = 0.5L (angle = 60) is a good test point. Note that I1THR = I2THR = 0 by default, which means that the phase-angle compensation value in X.PA0 is applied to the full range. Startup and select a target device The measurement values are continually refreshed at the rate of one update per second. Active powerbalanced loads >. (See theConnection communication/JTAG cablessection below.) The MAXQ3180 has three voltage channels, four current channels, and an internal channel for temperature measurement. Phase angle For example the Vector Sum tab is only available when the MAXQ3183 is selected as the target device. Linearity calibration The reference meter displays a limited number of parameters on the LCD: target device name, the serial-port baud rate compiled into the host firmware, and various power- and energy-measurement values. Balanced loads (IA + IB + IC) To perform a field firmware upgrade, you will need a MAXQ JTAG adapter and a program for loading the code, both of which can be obtained either from a third party or from Maxim. Select File, then Load Code from the menu. Figure 7. Connecting the reference meter to tester and PC. Display sequence on the LCD. Figure 1. What product(s) will you be manufacturing with these Maxim parts? This tool makes it very easy to monitor the settling effect of filters on any of the measurement parameters, such as power and current or voltage. Read register RegName N times, where N is an optional argument. Phase angle calibration is typically done at PF = 1.0 and PF = 0.5L. Refresh the Configuration tab (F5 or System Commands then Pool all Registers) to view the configuration values for this meter. Again two modes of calibration are supported: "by Meter" and "by Source." Figures 7 through 10 show the schematics of the hot board. In a single-range calibration the range High must be selected and I1THR and I2THR must be set to 0. In the "by Meter" calibration mode, the user inputs the four current levels expressed in percentage of Ib (%Ib) and the relative errors of active power at the four current levels. Two of the parameters (EnableDataLog, HarmonicDly) need to be edited in this file directly, when necessary. The pink color strip on the cable should face the LCD screen when properly connected (Figure 14). Unbalanced loads (IA + IB + IC) Schematic of the hot board showing the AFE. Note that the MAXQ3180 reference design will stop executing application code and the LCD will be blank during programming. . Active powerfrequency influence It then quickly returns to STOP mode. The software also provides many calibration screens for performing various meter calibrations like gain, phase angle, and linearity. Schematic of the cold board showing the microcontroller and LCD. Two modes of vector sum are supported in the MAXQ3183: 3-current vector sum and 4-current vector sum. Gain can be calibrated for each of the three phase voltages, and the three phase currents and neutral current. Gain factor is computed from the measured error (e) as follows: G is converted into a 16-bit unsigned integer before writing to the MAXQ3180 Gain register. Note that these values are not used in the compensation calculation, but are displayed for information only. All other parameters can be changed in the GUI software. Once the target device has been selected, configure the serial port. LSB for virtual current registers in nA VLSB = 1 means a value of 1 in the virtual current registers, so (I.X, X = A, B, C) represents 1nA. However, the metering board does have input nodes for the neutral current. The design implements a basic three-phase electric meter system using the MSP430F449 smart meter SoC: the LMV324 precision op amps: and TPS76333 LDO regulator . Unfortunately, we are unable to place your order due to restrictions on your account. The MAXQ3180 reference design uses resistor-dividers for voltage sensing and current transformers for current sensing. However, one could sacrifice one of the phase-current input terminals and use that for neutral current. The MAXQ3180/MAXQ3183 reference designs can be ordered online. Schematic of the hot board showing the isolation. Saves the configuration parameter into an XML file. Active powerphase C These loads are not necessarily the highest and lowest operating points. Harmonics: IEC phase fired current waveform (IEC 60235:21) The processing flow for "by Source" mode is shown below. The first block of data is the register values (in hex) of the current RMS registers. The two-board design uses a hot board for the metrology circuits and a cold board for the host microcontroller, communication, and display (Figure 5). Note that the metrology board supports neutral current inputs, but there are no meter terminals for the neutral current inputs (Figure 6). Sorry, but we are unable to process sample requests from non-business or non-educational e-mail addresses via this site. LSB for virtual power registers in nW, VLSB = 1 means a value of 1 in the virtual power registers, so (PWRP.X, PWRQ.X, PWRS.X, PWRPF.X, PWRQF.X, PWRSF.X, X = A, B, C) represents 1nW. Feature Comparison for the Polyphase Metering AFE Devices. The design uses a capacitive-drop power supply based on the TPS76333 to provide a low-cost power supply solution. Reference Design for an Energy Meter Using the MAXQ3180/MAXQ3183 AFEs, Low-Power, Multifunction, Polyphase AFE with Harmonics and Tamper Detect. Schematic of the cold board showing power and communications. The application code (residing in the MAXQ2000)) and PC software support both AFEs. Note that this operation does not alter the settings stored in the flash memory. A similar test was performed with unbalanced loads. All configuration parameters in the Conversion Settings group box except the Temp. They are not necessarily the highest and lowest operating points. Note that this value is for information only; it is not used in the gain factor calculation. All updates will be posted on Maxim's website. Simply check the Apply to All Phases checkbox. Unscrew the two tie-down screws for the terminal cover (at the bottom of the meter case). Turn the meter bottom side up and unscrew the two screws. Note that data were taken with different meters at various times. Be careful when saving a configuration to flash, as this will overwrite all previously saved meter configuration values; it can also impact meter operations or performance. Restores default setting values into MAXQ3180's RAM. The computed gain factor can be applied to all three phases by checking the Apply to All Phases check box. This refreshing action not only pulls the configuration values from the MAXQ2000 flash for displaying in the software, but it also stores them in the software memory for use in any subsequent computations. Schematic of the hot board showing the power management. Temp. In addition to each individual read, the average value of the N reads is displayed. Enter this measurement into the Percent Error (%) text box on the dialog screen. MAXQ3180 registers More detailed image (PDF, 1.4MB) From the Script Debugging tab, click the Help button to print a list of the supported commands. 123 0 obj
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Power script The meter design uses two boards. Click Connection on the menu and select Connect. In the Target menu, click Connect to MaxQ Loader. and cycle the power to the meter. Click on the Read button to read the phase angle as seen by the meter. Country. Temperature, system frequency, and voltage phasor angles (with respect to phase A) are also presented on this tab. The "by Meter" mode is preferred because it uses the errors of active power in computing the correction values. Calibrating in balanced loads condition takes much less test time compared to calibrating each phase individually. N should be specified in decimal and defaults to 1 if unspecified. Some meters were built with current transformers of 1.5(9)A and others of 1.5(6)A. All updates will be posted on Maxim's website. Figure 5. BOM listing for the cold board More detailed image (PDF, 357kB). After entering the value, click the Read button to retrieve the value measured by the MAXQ3180. See the download link above for more information regarding the software installation and requirements. (Harmonic components measurement is supported in the MAXQ3180 as well.) Hardware and software design files are provided to enable calculation of various parameters for three-phase energy measurement: such as RMS current & voltage: active and reactive power and energies: power factor and frequency. If you decide to start from a proprietary design and boards, the schematics and layout files for this reference design are available from Maxim. Reads all registers associated with the currently active tab. The "by Meter" mode is the preferred calibration mode because it minimizes the error of active power. Low 1 should be selected so that the input amplitude on the MAXQ3180's current input pins is close to, but lower than (VREF/2)/32 (0.032V). Calibration should follow the sequence outlined below where the dashed steps may not be required depending on the requirement for design accuracy. More detailed image (PDF, 334kB) The software controls the meter only and does not control any meter tester, so the process is not fully automated. Close-up view of the connectors from the energy-meter reference design to a meter tester. Active powerphase A For the reference design part numbers and ordering instructions, see the Order information section below. Click the Exit Stop button to exit stop mode. Voltage transducer value in volts. Proper connection of the JTAG cable to the cold board. 123-456-7890 Loads the contents of the configuration file into the software. Unscrew the hold-down screws for the meter's top cover plate. A brief description of the resolution variables are given below. Both angles are included in the standard meter-accuracy test sweep. City, State, Zip/Postal Refer to the AC terminal descriptions above and to the meter tester's manual for instructions on how to connect the meter to a meter tester (Figure 3). Note that for "by Source" to work well, the test point should be set far from PF = 1.0. The MAXQ3181 is fully pin compatible with the MAXQ3180 and its registers are a subset of the MAXQ3180's registers. Next, click on the Calculate Gain Factor button to compute the corresponding hex value for the Gain register. The MAXQ3180 reference design uses the MAXQ2000 microcontroller to implement communications, display, and other user-interface functions. The reference design can be purchased online. Vector sum (MAXQ3183 only) Refer to Figure 2 when making AC connections between the reference-design meter and a meter tester. Our free samples program limits the quantities that we can provide to each customer per calendar year.If you feel that you have received this message in error, please contact samples-admin@maximintegrated.com. More detailed image (PDF, 1MB) System commands If the application code needs updating, connect the JTAG cable. Click the Calculate OFFS_HI button to compute OFF_HI, OFFS_LO, and GAIN_LO. Linearity calibration smoothly joins and flattens two error curves, one from the high range and one from the low range. For more information see the device data sheet. Measurement of neutral current is not supported by the reference design because dedicated AC-input terminals are not available on the meter case. The result was presented as the ratio of the harmonic component magnitude with respect to the fundamental component. Check the Apply to All Phases checkbox if the same correction value is to be applied to all three phases. The error needs to be corrected before you proceed. Figure 4 illustrates the display sequence. More detailed image (PDF, 376kB) The application code can be loaded through the onboard JTAG port. Do not load more than 6A over an extended period of time. Figure 6. Changing a dropdown item has the same effect. The screws and connections immediately below the board are not safe to touch, however. Your next step can be as simple as requesting a few samples. Note that these values are for information only and not used in the subsequent calculations. Figure 2. The rating of the current transformers can be found on the transformers themselves. If this were done, clicking the Neutral Current button would cause the MAXQ3180 to perform a neutral current measurement on demand. All gain calibrations share the same flow. The second block of data is the register values converted to amperes. Not available for sale. In the "by Source" mode, the input is the source phase angle. For each phase and total of the three phases plus neutral, the Status tab displays: the RMS of voltage and current, real/reactive/apparent power, power factor, and fundamental powers (real/reactive/apparent). This mode is intended for operation on a battery supply (i.e., when an AC main is not present). Visit My Quotes Thank you! K is an integral part of the command and signifies the length of the target register (in number of bytes): Write value V to register named RegName, where V is expressed in hex. Since the meter case of this reference design does not have input terminals for the neutral current, we tested the 3-current vector sum only. Two forms of vector sum are supported: See the dedicated application note 4664," Calibration Meter configuration Communication between the hot and cold board is through the SPI connector, which is isolated on the hot board. The message "Successful in communicating with MaxQ Bootloader" will appear to confirm proper operation. RAM registers map It supports most of the MAXQ3180's metering features. The hot board in the reference design had four channels to measure current. If an update to the host application code is required, a serial-to-JTAG programming adapter should be used to reload the code into the MAXQ2000 microcontroller. Gain factor is computed from the Source Reading (V) value (VSOURCE) and the Meter Reading (V) value (VMETER) as follows. Low-Cost Three-Phase Electricity Meter Reference Design, Three-phase electricity meter that meets Class 0.5 accuracy requirements from ANSI and IEC TI Energy Library firmware calculates all energy measurement parameters including active and reactive power and energy: RMS current and voltage: power factor: and line frequency Built-in 160-segment display Powered from three-phase line voltage. The "by Source" option is for a setup in which the calibration set point (value) is provided by the meter tester. Also learn about new tools and technical training resources. The meter communicates with a PC through an RS-232 serial port, which is hidden inside the meter case. The board layout and connection terminals for the energy-meter reference design. X_CC is computed using the conversion settings: If any one of the X_CC values does not match, an error window alerts you. This value should be entered into the Source Reading (V) text box on the dialog screen. You will receive an e-mail notification if you subscribe to Maxim EE-Mail. Please click here to place an order. Power down the MAXQ3180 reference meter before proceeding! We will need the following information in order to respond to your Quote Request. Check the Apply to All Phases checkbox if the same correction value is to be applied to all three phases. In most cases, though, if the voltage and current are accurately calibrated, the power-gain calibration is not needed. When the PC software first connects with a reference meter, it checks the conversion settings (read from the Configuration File) for consistency with the X_CC (VOLT_CC, AMP_CC, PWR_CC, and ENR_CC) values stored in the MAXQ2000. Rather, the PC software computes phase angles from the active and reactive powers measured by the MAXQ3180. For example, in the above screen shot calibration is done for voltage and current only, since the Target entry box for power is empty. Click the Calculate OFFS_HI button to compute OFF_HI, OFFS_LO, and GAIN_LO. Click the Read button to retrieve the measured value by the meter. The meter should start running by displaying the device name (MAXQ3180 or MAXQ3183) as the first message on the LCD screen. The result can be exported to a CSV file too. Figure 14. Again, two calibration modes are supported: "by Source" and "by Meter." When testing the reference meter on your system, make sure to limit the current input to below the maximum rating of the current transformers. The LMV324 op amps are used for conditioning the voltage and current signals coming from the current transformers. %PDF-1.4
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Its easy! Our dedicated team of Applications Engineers are also available to answer your technical questions. An SPI port is provided for interfacing with a host controller.
The MAXQ3180 and MAXQ3183 are two of the three polyphase AFE devices from Maxim Integrated. See https://my.maximintegrated.com/subscriptions/ee_mail/index.mvp for instruction on subscribing to ee-mail. Then make the necessary software changes in your host controller to control the MAXQ3180/MAXQ3183. Clicking the Enter Stop button will cause the MAXQ3180 to enter stop mode. The two boards communicate through an isolated SPI link. Below is the screen capture of a test using the MAXQ3183. Loading code with MTK is illustrated below. The MAXQ3180 reference-design system block diagram. The target device must be selected at the startup screen since features are grouped by functions; the availability of function tabs varies according to the target device. The most intuitive way to demonstrate the metering functions is to present them graphically. File Operations The meter case does not support a neutral current input, as there are only three current input pairs (terminals). Current RMSphase A/B/C email@mycompany.com Use the following steps to open the meter case and connect the serial communication and JTAG cables. Table 1. Click Exit LOWPM to return to normal operation mode. The third block is the expected value of 3-current vector sum, which should be 0 since the loads are balanced. The PC software will display a dialog box that lists all the available serial ports. This board is directly connected to the AC neutral and is, therefore, not safe to touch. The "hot board" mounted below the cold board contains the AC-input circuits and the target device (e.g., MAXQ3180/MAXQ3183). Reactive powerbalanced loads More detailed image (PDF, 248kB) Three File operations are supported and described below. Saves the current MAXQ3180 register values into the MAXQ2000's flash memory. Gain Figure 4. Consequently, the same reference design can be used to evaluate the MAXQ3181. Do not touch the hot board! In most designs the sense circuit does not change its phase dependency with respect to loading levels, in which case a single-range calibration is sufficient. In the "by Source" calibration mode, the user inputs the four current levels expressed in percentage of Ib (%Ib). Search our knowledge base for answers to your technical questions. Power gain can be calibrated too, if necessary. Note that in the "by Source" mode, the correction value is computed from the difference in phase angle rather than the error of active power. -,e\_QC,XFIj:nvsW=9*`A&VFLrNn3WiPBpzA49U9i]Rn]"m The Exit Stop button implements option c. Clicking Enter LOWPM will cause MAXQ3180 to enter the low-power measurement mode. Note that for any gain calibration, it is recommended that you initialize the Gain register value before proceeding. The vector sum feature is available in MAXQ3183 only, and is an on-demand feature. The PC software provides a convenient way to evaluate the reference meter. Make sure that the JTAG cable pin 1 is connected to the pin 1 of the JTAG header on the board. More detailed image (PDF, 285kB), The main board includes a MAXQ2000 supervisory microcontroller unit, an LCD display, and communications (Figure 11). With this design developers can quickly determine that the MSP430F449 e-meter SoC meets the requirements for their low-cost smart e-meter. Restores the values saved in MAXQ2000's flash back to the MAXQ3180's RAM registers. In a single-range calibration, the range High must be selected and I1THR and I2THR must be set to 0. Typical choices for the source angles are 0 degrees (PF = 1.0) and 60 degrees (PF = 0.5L). When code has been successfully downloaded to the MAXQ2000, you will see the Loading Completed Successfully message. These commands facilitate operations with the reference meter. Remove the terminal cover by pulling it upward. Because the MAXQ3180 supports phase compensation in three ranges, the software can minimize the effect of poor current transformer phase behavior. The reference meter illustrates the metering functions of the MAXQ3180 and MAXQ3183 energy meter AFEs.
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