Texas Instruments ADS1131REF Скачать руководство пользователя страница 2

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Contents

Getting Started

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Weigh Scale Mode

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Analysis Mode

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Using the PC Software

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Serial Console

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Hardware

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Appendix A

Schematic and Layout

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List of Figures

ADS1x31REF Controls and Connectors

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4-Wire Load Cell to Terminal Block

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6-Wire Load Cell to Terminal Block

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4-Wire Load Cell to Header

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6-Wire Load Cell to Header

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ADS1231REF PC Software Display

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ADS1x31REF Average Data

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ADS1x31REF Hardware Block Diagram

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ADS1x31REF PCB

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Top Side

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ADS1x31REF PCB

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Layer 1

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ADS1x31REF PCB

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Layer 2

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ADS1x31REF PCB

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Bottom Side

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ADS1x31REF Schematic

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ADC

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ADS1x31REF Schematic

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MCU

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ADS1x31REF Schematic

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USB

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List of Tables

Unit Conversion Factors and Display Formats

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Parameters in Configuration Mode

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Modes and Example Displays

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Voltage Display Ranges

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Parameters in Analysis Mode

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Console Mode Commands

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Load Cell Header Pinout

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Terminal Block Pinout

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ADS1x31REF Bill of Materials

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ADS1131REF and ADS1231REF

SBAU175A

–

July 2010

–

Revised August 2011

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2010

–

2011, Texas Instruments Incorporated

Содержание ADS1131REF

Страница 1: ...of design Eight digit starburst LCD readout USB connection for firmware updates and remote control Designed for very low power consumption Battery 9V or wall power Version 1 0 0 of the firmware includes the following features Weigh scale mode with two point calibration Complete configuration of the device Real time peak to peak and RMS noise calculation Autoranging voltage display Noise displayed ...

Страница 2: ...20 9 ADS1x31REF PCB Top Side 25 10 ADS1x31REF PCB Layer 1 25 11 ADS1x31REF PCB Layer 2 26 12 ADS1x31REF PCB Bottom Side 26 13 ADS1x31REF Schematic ADC 27 14 ADS1x31REF Schematic MCU 27 15 ADS1x31REF Schematic USB 28 List of Tables 1 Unit Conversion Factors and Display Formats 8 2 Parameters in Configuration Mode 9 3 Modes and Example Displays 11 4 Voltage Display Ranges 12 5 Parameters in Analysis...

Страница 3: ... are taken directly from the installed ADS device and various measurements are made upon them Several measurements are available including raw display voltage RMS noise and peak to peak measurements The ADS1131 or ADS1231 can also be configured directly from this mode Analysis mode is described in detail in Section 3 Configuration mode Parameters governing the operation of the ADS1x31REF can be vi...

Страница 4: ...ration it should be set to JTAG 1 3 Power To apply power to the ADS1x31REF connect a 9V battery or plug in a 6V 9V ac wall adapter AC adapters must be tip positive sleeve negative When an ac adapter is plugged in the board always takes power from it and not from the battery The ADS1x31REF is protected against polarity reversal If a power source is connected in reverse by mistake the display remain...

Страница 5: ...by the 5V power supply and the ADC reference is taken from the power supply Figure 4 4 Wire Load Cell to Header For this configuration the reference select switch must be in the 5VA position the EXT position does not work 1 4 4 Connecting a 6 Wire Load Cell to the Header Figure 5 shows the connection of a 6 wire load cell to the header In this configuration the load cell is excited by the 5V power...

Страница 6: ...nts given in the product data sheet are taken with the inputs shorted to 2 5V These noise measurements can be replicated on the ADS1x31REF with no external hardware To set up these measurements on the ADS1x31REF perform the following steps 1 Move the mode switch to Analysis mode 2 Short jumpers J8 and J7 These jumpers are located very near the terminal block and are marked Input Shorting Jumpers i...

Страница 7: ... connected disconnect them see Figure 1 3 Obtain a weight of known mass 4 If the mass of the weight is not equal to the configured calibration mass adjust the calibration mass as described above 5 Move the mode switch to SCALE position If calibration has not been performed the display reads NO CAL 6 Press the CAL button and follow the calibration procedure given in Section 2 3 If the calibration i...

Страница 8: ...ollowed by st followed by pounds displayed to two decimal places 2 1 1 Calculation of Mass Mass is calculated from ADC code using the formula w m c wzs wt where w mass c the ADC code wt tare weight m wzs wt values determined in the calibration process m is a calibration constant and is calculated using Equation 1 1 where wfs is the user specified calibration mass cfs is the ADC code taken with the...

Страница 9: ... mode To enter configuration mode press the PARM buttons simultaneously The four buttons then assume the functions shown in the CONFIG box To exit Configuration mode press the PARM buttons simultaneously again This function does not cause parameters to be adjusted because only button releases are detected in Configuration mode Configuration mode contains a number of adjustable parameters To scroll...

Страница 10: ...of the available units in three significant figures The unit is independent of the display unit Each digit in the mass is adjusted separately The currently selected digit flashes and can be adjusted with the VALUE buttons The PARM buttons are used to select the digit The unit is adjusted in the same manner and flashes when selected When the unit is changed the value changes to the equivalent mass ...

Страница 11: ... name on the display The measurement modes are described in detail in Section 3 2 The ADS1131 or ADS1231 itself can be configured directly from this mode as described in Section 3 1 3 1 Switch Functions NEW BLOCK Pressing this switch resets the collection process for the RMS peak to peak and averaged measurements UNIT Cycles between available units Not all units are available in all modes DISP Whe...

Страница 12: ...n effective number of bits ENOB For decimal codes sN is displayed directly Hexadecimal is not available because sN may be fractional For volts sN is converted to a voltage as in raw mode ENOB E is calculated using Equation 5 5 Where N is the maximum number of available bits 18 for the ADS1131 and 24 for the ADS1231 The zero case is needed when a string of equal codes is read This can happen when t...

Страница 13: ...mmands or gateways to a submenu These items are labelled as words with a question mark To enter these items or to execute the command press SEL or ENT Although a few of the parameters in the Analysis and Scale configuration menus are the same the settings are kept separate between the modes Table 5 summarizes the available parameters Table 5 Parameters in Analysis Mode Parameter Display Value Rang...

Страница 14: ... uninstalls it and quits You must run the installer again to complete the installation If the Virtual COM Port driver is already installed the installer offers to uninstall it Do not uninstall it cancel this part of the installation The installer displays messages reminding you of these points 4 1 1 First Time Connection of the ADS1x3xREF If the ADS1x31REF has never been connected to your computer...

Страница 15: ... Although this procedure is conceptually simple it may not go as smoothly as expected The following process ensures that the board is found correctly Note that Steps 1 3 can be done in any order Step 1 Apply power to the ADS1x31REF Step 2 Plug in the USB connector Step 3 Start the program Step 4 Watch the status display It reads Scanning followed by the name of the serial port being tested When th...

Страница 16: ...led and dimmed while Analysis occurs 4 6 1 Averaging The PC software can process data collected from the board using a sliding window averager The controls for the averager are found in the Averager box To turn the averager on use the Averaging switch The number of points averaged is set by the Points control and the number of points currently collected is shown in the Collected box When the avera...

Страница 17: ...erence is normally taken from the 5V power supply If a different reference voltage level is used the value of Vref should be changed to reflect the different level so that voltage calculations are performed correctly The Vref control also affects voltages recorded in Record mode 4 6 5 Block Acquisition To enable the program to run reliably on slower computers results are not calculated each time a...

Страница 18: ... correct 5 Serial Console The ADS1x31REF provides a console mode that can be used with any Windows terminal emulation program such as Hyperterm In Windows this configuration is done through the Virtual COM Port driver supplied with the EVM software causing the ADS1x31REF to appear in Windows as an extra serial port 5 1 Using the Console To use the console load a terminal emulation program and conn...

Страница 19: ...he console and standalone modes parameters may become out of sync 5 2 Command Reference 5 2 1 P Set PGA This command has no effect on the ADS1131 or ADS1231 because the device gain is fixed P with no argument prints the current gain setting 5 2 2 R Set Data Rate This command sets the speed of the installed ADS device according to these parameters RF sets rate to fast RS sets rate to slow R with no...

Страница 20: ...sample from the installed ADS device The sample is displayed in raw hexadecimal 5 2 6 C Set Channel This command has no effect on the installed ADS device because there is only one channel C0 set to channel 0 C with no arguments prints the current channel always CHAN 0 5 2 7 Q Query Parameters Q causes the ADS1x31REF to issue a coded string summarizing the current settings The format of the string...

Страница 21: ...the digital circuitry 6 4 1 Input Circuitry The ADS1x31REF is designed to connect to resistive bridge sensors particularly load cells The input channel is filtered by pass through capacitors C38 and C39 and differential capacitor C7 Common mode capacitors C32 and C29 provide additional RF rejection 6 4 2 Load Cell Header The load cell header J6 provides a convenient terminal for load cells having ...

Страница 22: ...mpers J7 and J8 are provided Jumper J8 shorts the inputs together Jumper J7 connects the inverting input to a voltage divider made from R25 and R26 dividing the power supply by 2 This voltage divider electrically resembles an ideal bridge sensor 6 5 USB Interface The USB interface can be used for firmware download or data communications Its role in firmware download is discussed in Section 6 6 The...

Страница 23: ... 4 22pF C1 C2 C16 50V Ceramic Chip Capacitor 5 TDK C1608C0G1H220J C17 C0G 4 4 4 100pF C29 C30 16V PPS Film Chip Capacitor 2 Panasonic ECH U1C101GX5 C31 C32 5 4 4 100pF C40 C41 Filter High Frequency 100pF Murata NFM21CC101U1H3D C42 C43 6 5 5 0 01μF C5 C11 50V Ceramic Chip Capacitor 10 TDK C1608X7R1H103K C13 C14 X7R C15 7 6 6 0 1μF C12 C21 50V Ceramic Chip Capacitor 10 TDK C1608X7R1H104K C33 to C36 ...

Страница 24: ...1 SW7 DPDT Slide Switch Top Actuator NKK SS22SDP2 39 1 1 SW8 SPDT Slide Switch Top Actuator NKK SS12SDP2 40 1 1 SW9 4PDT Slide Switch RA Actuator E Switch EG4208 41 0 0 TP1 to TP14 Not Installed TP16 to TP18 42 1 1 TP15 Testpoint Keystone 5011 Electronics 43 1 0 U6 Two Channel Analog to Digital Texas Instruments ADS1131ID Converter 0 1 Two Channel Analog to Digital Texas Instruments ADS1231ID Conv...

Страница 25: ...A 2 PCB Layout Figure 9 ADS1x31REF PCB Top Side Figure 10 ADS1x31REF PCB Layer 1 25 SBAU175A July 2010 Revised August 2011 Schematic and Layout Submit Documentation Feedback Copyright 2010 2011 Texas Instruments Incorporated ...

Страница 26: ... com Figure 11 ADS1x31REF PCB Layer 2 Figure 12 ADS1x31REF PCB Bottom Side 26 Schematic and Layout SBAU175A July 2010 Revised August 2011 Submit Documentation Feedback Copyright 2010 2011 Texas Instruments Incorporated ...

Страница 27: ...DOUT J2 CUI STACK PJ 102BH VIN 1 VOUT 5 GND 2 NR ADJUST 4 ENABLE 3 U1 TPS76350DBV BT1 9V C8 10uF D1 C11 0 01uF C19 10uF C20 10uF TP3 5V TP4 3 3VD 3 3VD 5V 5VA C9 1uF J5 OST_ED555 2DS FB SENSE 1 RESET 2 EN 3 GND 4 IN 5 IN 6 OUT 7 OUT 8 U2 TPS77133DGK RST R27 47K DVDD 1 GND 2 CLKIN 3 SPEED 4 CAP 5 CAP 6 AINP 7 AINN 8 VREFN 9 VREFP 10 GND 11 AVDD 13 PSW 12 PDWN 14 SCLK 15 DRDY DOUT 16 U6 ADS1231ID AD...

Страница 28: ...M 1 COM 0 S 38 S 37 S 36 S 35 S 34 S 33 S 32 S 31 S 30 S 29 S 28 S 27 S 26 S 25 S 24 S 23 S 22 S 21 S 20 S 19 S 18 S 17 S 16 S 15 S 14 S 36 S 35 S 34 S 33 S 32 S 31 S 30 S 29 S 28 S 27 S 26 S 25 S 24 S 23 S 22 S 21 S 20 S 19 S 18 S 17 S 16 S 15 S 14 S 5 S 6 S 7 S 8 S 9 S 10 S 11 S 12 S 13 S 5 S 6 S 7 S 8 S 9 S 10 S 11 S 12 S 13 C5 0 01uF C23 2 2uF C24 2 2uF SW8 NKK_SS12SDP2 R16 10K 3 3VD R18 47K D...

Страница 29: ...bration from Table 5 13 Removed information about Offset Calibration from Section 3 4 1 13 Updated Table 6 to remove Offset Calibration information 19 Deleted Offset Calibration section from Command Reference section 19 NOTE Page numbers for previous revisions may differ from page numbers in the current version 29 SBAU175A July 2010 Revised August 2011 Revision History Submit Documentation Feedbac...

Страница 30: ...e product This notice contains important safety information about temperatures and voltages For additional information on TI s environmental and or safety programs please contact the TI application engineer or visit www ti com esh No license is granted under any patent right or other intellectual property right of TI covering or relating to any machine process or combination in which such TI produ...

Страница 31: ...horized for use in safety critical applications such as life support where a failure of the TI product would reasonably be expected to cause severe personal injury or death unless officers of the parties have executed an agreement specifically governing such use Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications and acknowledge ...

Страница 32: ...Mouser Electronics Authorized Distributor Click to View Pricing Inventory Delivery Lifecycle Information Texas Instruments ADS1131REF ...

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