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CY8CKIT-025 PSoC® Precision Analog Temperature Sensor Expansion Board Kit Guide, Doc. # 001-65791 Rev. *J

25

Hardware

Figure 4-1. Thermocouple Circuit Diagram

The cold junction compensation IC measures the cold junction temperature and outputs a voltage
proportional to the temperature. The ADC measures the cold junction output voltage to calculate the
cold junction temperature. This temperature is used to calculate the cold junction compensation,

V2

.

V1

is measured in the first ADC channel. The temperature can be calculated using equation 1 if

V1

,

V2

, and

K

are known.

The lower potential lead of the thermocouple connector is biased at a potential above ground so that
negative temperatures up to –270 °C can be measured after accommodating for small negative
device offset. PSoC Creator provides a thermocouple component that supports all thermocouple
types (B, E, J, K, N, R, S, and T) and simplifies voltage-to-temperature conversion and vice versa.

4.3

Thermistor

Application note

AN66477 - PSoC 3 and PSoC 5LP Temperature Measurement with Thermistor

explains the thermistor theory and temperature measurement with thermistor. This section assumes
that you are aware of thermistor fundamentals and terminology.

The thermistor resistance changes with temperature in a nonlinear fashion. Thermistor
manufacturers provide the thermistor temperature versus resistance table. The Steinhart-Hart
equation (equation 2) characterizes thermistor resistance change with temperature to a good
accuracy and can be used to find temperature from thermistor resistance.

Equation 2

where,

-

A

,

B

, and

C

are the Steinhart-Hart coefficients

-

R

is the resistance at temperature

T

expressed in Kelvin

shows the circuit diagram used for the measurement. An excitation voltage is applied

across a series combination of thermistor and precision reference resistor, and the voltages across
thermistor and reference resistor are measured.

3.3 V

ADC

Thermocouple

Connector

330 k

1.5 k

M

U
X

IC

0

1

2

3

)

ln(

ln

1

R

C

R

B

A

T







«
...
23
24
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27
...
»

Содержание CY8CKIT-025

Страница 1: ...PSoC Precision Analog Temperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J Cypress Semiconductor 198 Champion Court San Jose CA 95134 1709 Phone USA 800 858 1810 Phone Intnl 408 943 2600 www cypress com ...

Страница 2: ...IES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PUR POSE To the extent permitted by applicable law Cypress reserves the right to make changes to this document without fur ther notice Cypress does not assume any liability arising out of the application or use of any product or circuit described in this document Any information provided in this document including any sample design information or...

Страница 3: ...oftware Installation 15 3 Kit Operation 18 3 1 Kit Overview 18 3 2 Kit Connections 18 3 3 Temperature Sensors 21 3 3 1 Thermocouple 21 3 3 2 Thermistor 21 3 3 3 RTD 22 3 3 4 Diode 22 3 4 Prototype Boards 23 4 Hardware 24 4 1 System Block Diagram and Theory of System Operation 24 4 2 Thermocouple 24 4 3 Thermistor 25 4 4 RTD 26 4 5 Diode 28 5 Example Projects 30 5 1 Overview 30 5 1 1 Migrating Proj...

Страница 4: ... 56 5 3 3 Project Details 58 5 3 3 1 Project Schematic 59 5 3 3 2 Component Configuration 61 5 3 3 3 Firmware Description and Flowcharts 64 5 4 Thermal Management 68 5 4 1 Project Description 68 5 4 1 1 Thermal Management EBK Description 68 5 4 1 2 Using TME EBK with CY8CKIT 025 69 5 4 2 Project Operation 70 5 4 2 1 Hardware Connections 70 5 4 2 2 Run Thermal Management System Firmware 74 5 4 2 3 ...

Страница 5: ...the factory default may affect its performance and cause interference with other apparatus in the immediate vicinity If such interference is detected suitable mitigating measures should be taken The CY8CKIT 025 as shipped from the factory has been verified to meet with requirements of CE as a Class A product The CY8CKIT 025 contains electrostatic discharge ESD sensitive devices Electrostatic charg...

Страница 6: ...res only at an ESD workstation If one is not available use appropriate ESD protection by wearing an antistatic wrist strap attached to chassis ground any unpainted metal surface on your board when handling parts Handling Boards CY8CKIT 025 boards are sensitive to ESD Hold the board only by its edges After removing the board from its box place it on a grounded static free surface Use a conductive f...

Страница 7: ...couples measure temperatures in a wide range from 250 C to 2300 C However the voltage change is not linear and takes more CPU cycles for temperature computation Thermocouples require another temperature sensor such as the thermistor diode or RTD to measure the cold junction temperature The DS600 IC or the thermistor can be used for cold junction compensation of the thermocouple A thermistor diode ...

Страница 8: ...ch type of temperature sensor With the 20 bit ADC of the PSoC it is possible to obtain a 0 1 C resolution easily with all four sensors The accuracy varies in each case depending on the method of measurement and the sensor used See the Hardware chapter on page 24 for details The Sequenced ADC example project includes three temperatures RTD temperature diode and IC temperature sensor as well as mill...

Страница 9: ...mal Management System example project supports fan control applications Add the CY8CKIT 036 EBK with two four wire fans to the CY8CKIT 025 EBK and a development kit to support complete temperature based fan control solutions For more details on CY8CKIT 036 PSoC Thermal Management EBK see the Cypress website 1 1 Kit Contents The CY8CKIT 025 PSoC Precision Analog Temperature Sensor EBK includes CY8C...

Страница 10: ...mperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J 10 Introduction Figure 1 1 CY8CKIT 025 Kit Contents 2x20 Pin Connector for Development Kit Interface r RTD Section r Thermistor Section r Diode Section r Thermocouple Section ...

Страница 11: ...re Installation chapter on page 15 to install the kit See the Kit Operation chapter on page 18 and Hardware chapter on page 24 to understand the kit operation and hardware The Example Projects chapter on page 30 explains the details of the firmware and provides steps to run the projects 1 4 Additional Learning Resources Visit www cypress com go psoc3 for additional learning resources in the form o...

Страница 12: ... Start Page of PSoC Creator or navigate to File Open Example Project Figure 1 2 Find Example Project The Find Example Project section has various filters that help you locate the most relevant project PSoC Creator provides several starter designs These designs highlight features that are unique to PSoC devices They allow you to create a design with various components instead of creating a new empt...

Страница 13: ...ts can be converted for use with CY8CKIT 030 PSoC 3 Development Kit or CY8CKIT 050 PSoC 5LP Development Kit by following the procedure in the knowledge base arti cle Migrating CY8CKIT 001 DVK project to CY8CKIT 030 050 Apart from the example projects and starter designs that are available within PSoC Creator Cypress continuously strives to provide the best support Click here to view a growing list...

Страница 14: ...icc Italics Displays file names and reference documentation Read about the sourcefile hex file in the PSoC Designer User Guide Bracketed Bold Displays keyboard commands in procedures Enter or Ctrl C File Open Represents menu paths File Open New Project Bold Displays commands menu paths and icon names in procedures Click the File icon and then click Open Times New Roman Displays an equation 2 2 4 T...

Страница 15: ...l the same this does not prevent kit installation Note that Adobe Reader is required to view the kit documents The installer also installs the example projects user guide quick start guide and other kit related documents as part of kit installation The installation steps are as follows 1 Insert the kit CD DVD into the CD DVD drive of your computer The CD DVD is designed to auto matically open an i...

Страница 16: ...ense You must activate this license within 30 days of installation When the Cypress software installation is complete and you run PSoC Creator activate the compiler license from Help Register Keil Note If there is a problem with Keil registration rename the _tools ini file in Install_Directory PSoC Creator version PSoC Creator import keil pk51 version to tools ini for the Keil registration to be s...

Страница 17: ...grammer already installed in your computer the installer will install only the kit related files in Install_Directory PSoC Precision Analog EBK version as shown in Figure 2 3 Figure 2 3 Installed Files After installation launch the example projects associated with the kit from the PSoC Creator Start Page as shown in Figure 2 4 Figure 2 4 PSoC Creator Start Page ...

Страница 18: ...rnal RTD The kit includes two diodes and a K type thermocouple Figure 3 1 CY8CKIT 025 PSoC Precision Analog Temperature Sensor EBK 3 2 Kit Connections The CY8CKIT 025 EBK connects to a development kit DVK using a 2 20 pin connector You can use the CY8CKIT 030 PSoC 3 DVK CY8CKIT 050 PSoC 5LP DVK or CY8CKIT 001 PSoC DVK The CY8CKIT 025 EBK can be connected to port E of the CY8CKIT 030 PSoC 3 DVK see...

Страница 19: ...CY8CKIT 025 PSoC Precision Analog Temperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J 19 Kit Operation Figure 3 2 Connect 2 20 Pin Connector to Port E of CY8CKIT 030 PSoC 3 DVK ...

Страница 20: ...og Temperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J 20 Kit Operation Figure 3 3 Connect 2 20 Pin Connector to Port E of CY8CKIT 050 PSoC 5LP DVK Figure 3 4 Connect 2 20 Pin Connector to Port A of CY8CKIT 001 PSoC DVK ...

Страница 21: ... used for cold junction compensation Because the onboard thermistor is not calibrated the IC DS600 is provided for cold junction compensation AN75511 Temperature Mea surement with Thermocouples provides an example project that demonstrates how to use the therm istor for cold junction compensation For more details about the thermocouple 5SRTC GG K 20 36 and IC DS600 see their datasheets in the foll...

Страница 22: ...xternal RTD to terminal blocks J8 and J9 The silk helps in the con nection Remove jumper J6 Internal onboard RTD Place jumper J6 On jumpers J8 and J9 short 1 2 Figure 3 7 shows the connections for an internal RTD Figure 3 7 RTD 3 3 4 Diode Terminal block J4 provides the option to connect up to two diode connected transistors The diodes are connected anti parallel see Figure 4 4 on page 29 to each ...

Страница 23: ... is to support four wire measurement so that the series resistance error can be avoided See the Diode section on page 28 for details This wire also shorts the base and collector of transistor 1 If you are installing only transistor 2 make sure you also have a wire between J4 3 4 so that the base and collector of transistor 2 are shorted Alternatively you can short the base and collector directly o...

Страница 24: ...e of thermocouple terminology A thermocouple gives an output voltage that is directly related to the temperature difference between two metallic junctions The output voltage is not linearly related to temperature The output voltage versus temperature curve can be considered piece wise linear with different slopes in different temperature ranges The relation between hot junction voltage and cold ju...

Страница 25: ...ltage to temperature conversion and vice versa 4 3 Thermistor Application note AN66477 PSoC 3 and PSoC 5LP Temperature Measurement with Thermistor explains the thermistor theory and temperature measurement with thermistor This section assumes that you are aware of thermistor fundamentals and terminology The thermistor resistance changes with temperature in a nonlinear fashion Thermistor manufactur...

Страница 26: ...ovides the flexibility of using either a lookup table LUT or the Steinhart Hart equation and provides simple C functions to compute temperature from resistance 4 4 RTD Application note AN70698 PSoC 3 and PSoC 5LP Temperature Measurement with RTDs explains the RTD fundamentals and RTD temperature measurement This section assumes that you are aware of the RTD terminology In an RTD the resistance var...

Страница 27: ... is used to accurately measure the current forced using IDAC thereby eliminating any gain error and drift associated with the ADC and IDAC First the IDAC current is passed through the reference resistor Rref and the voltage across the reference resistor Vref is measured using ADC The same current is then passed through the RTD and the voltage across RTD Vrtd is also measured using ADC The RTD resi...

Страница 28: ...on current is the constant that has a value between 1 and 2 depending on the material and physical structure of the diode VT is the thermal voltage calculated with the equation where k is the Boltzmann s constant T is the absolute temperature in Kelvin q is the magnitude of electron charge By passing two currents I1 and I2 and measuring the respective voltages V1 and V2 the temperature can be calc...

Страница 29: ...channel2 are active While measuring the temperature using diode D2 MUX1 channel2 and MUX2 channel1 are active By passing two currents I1 and I2 and measuring the respective voltages V1 and V2 the temperature is calculated using equation 8 The ADC measures a negative voltage in one of the two cases which can be negated in firmware to make it positive Measurements are made in four wire configuration...

Страница 30: ...ple project can be used for sensing applications requiring temperature measurement such as RTD and other types of voltage output sensors The example is also useful in system monitoring applications requiring temperature usually temperature diode or IC temperature sensor and voltage rail measurement This example project uses the ADC in 16 bit mode and provides higher throughput In this project the ...

Страница 31: ...035 Project Device Selector If the CY8CKIT 001 project is being updated to be used with the PSoC 5LP processor module you must also change the CMOD pin mapping from P2_7 to pin 15_5 To print floating point variables on the LCD set the Use newlib nano Float Formatting parameter to True under Project Build Settings Linker as shown in Figure 5 1 and change the Heap Size to 0x200 in the System tab in ...

Страница 32: ...he thermocouple which is the first item in the user selectable menu CapSense buttons P5_5 and P5_6 act as the scroll down and scroll up menu buttons respectively A mechanical switch connected to P6_1 is used to proceed through various calibration steps A CapSense slider is used to set the calibration temperature The menu has the following items Thermocouple temperature display IC temperature displ...

Страница 33: ...pping The project provided for the CY8CKIT 001 PSoC DVK can be used with both PSoC 3 and PSoC 5LP See Migrating Projects to use with CY8CKIT 050 and CY8CKIT 010 on page 31 for more details 5 2 2 1 1 CY8CKIT 030 PSoC DVK 1 Plug the PSoC Precision Analog Temperature Sensor EBK to port E of the CY8CKIT 030 DVK 2 No jumper wires are required for the PSoC 3 DVK examples because the mechanical buttons a...

Страница 34: ...IT 001 PSoC DVK 1 Plug the PSoC Precision Analog Temperature Sensor EBK to port A of the CY8CKIT 001 DVK 2 In the pin header breadboard area of the CY8CKIT 001 base board use jumper wires to make the following connections a SW1 to P1_7 b SW2 to P0_7 3 Set the system to run at 3 3 V using SW3 set J6 VDD DIG and J7 VDD ANLG to VDD 3 3 V ...

Страница 35: ...LCD displays a welcome message and the temperature reading from the thermo couple which is the first item in the user selectable menu SW2 can be used to toggle the cold junction compensation sensor between the IC DS600 and thermistor 7 Press CapSense button P5_5 to scroll down the menu and P5_6 to scroll up the menu 8 Use SW2 to proceed through the calibration steps see RTD Calibration on page 47 ...

Страница 36: ...ce of each onboard sensor is listed in Table 5 1 These numbers are from the respective sensor datasheets For diode the ideality factor is the source of its tolerance This number is generally not mentioned in the diode datasheet and must be determined experimentally Diode ideality factor generally lies between 1 and 1 01 An ideality factor difference of 0 004 using 1 008 instead of 1 004 causes an ...

Страница 37: ...nal filtering at the cost of temperature settling time The IIR filter can be changed in firmware as shown in Sensor Output Filter on page 51 5 2 2 4 3 Test Results This section shows the test results on the sample board Wherever possible measurement tech niques are used to identify the signal chain performance of PSoC Thermocouple Thermocouple input can be simulated by a millivolt source This elim...

Страница 38: ...s used to provide resistances in the whole RTD temperature range the RTD temperature measured by PSoC is noted 1 0 666 16 7 16 7 0 2 1 754 43 46 43 4 0 1 3 2 58 63 5 63 5 0 4 3 663 89 5 89 4 0 1 5 4 712 114 9 114 9 0 10 9 582 235 9 235 8 0 1 20 19 58 475 475 0 30 28 76 691 2 691 1 0 1 40 39 54 955 75 955 8 0 1 50 49 816 1227 1226 9 0 1 Table 5 4 Thermistor Test Results Resistance in ohms Multimete...

Страница 39: ...ing the expected temperature and comparing it to the temperature dis played by PSoC Sample test results at a few temperature points are shown in Table 5 7 Table 5 5 RTD Test Results Resistance in Ohms Multimeter Measurement Expected Temperature C Measured Temperature C Temp Measure Error Signal Chain C 79 85 51 1 51 3 0 20 100 06 0 2 0 2 0 00 110 76 27 6 27 7 0 10 120 25 52 2 52 1 0 10 133 85 5 85...

Страница 40: ...tion The IC temperature is about 0 3 C to 0 5 C lower than the RTD and thermistor temperature because the exposed pad underneath the IC is connected to ground This is an offset error This offset error can be eliminated by performing an offset correction as shown in IC Calibration on page 50 Apart from the above thermal considerations the sensor and bias resistor tolerances should deter mine the se...

Страница 41: ...CY8CKIT 025 PSoC Precision Analog Temperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J 41 Example Projects Figure 5 5 PSoC Creator Top Design ...

Страница 42: ...d in 16 bit mode Figure 5 6 shows the configuration used Figure 5 6 ADC Configuration The ADC Buffer Mode is set to Level Shift because many of the voltages being read are near VSS this setting yields better ADC results for signals near VSS 5 2 3 2 2 IDAC Configuration The IDAC is configured in the 0 to 255 µA range The IDAC is used for RTD and diode temperature measurements The IDAC data register...

Страница 43: ...e Figure 5 8 illustrates the steps involved in thermocouple temperature measurement This flowchart involves conversion of voltage to temperature and vice versa The conversion is done using thermocouple calculator component which in turn uses the polynomial provided by NIST The mathematical conversion results in an error less than 0 07 C The example project uses a K type thermocouple The component ...

Страница 44: ...rmocouple Flowchart Read Vssa Ref voltage for correlated double sampling CDS Convert CJ voltage to CJ temperature Convert CJ temperature to CJ compensation voltage Read hot junction voltage perform CDS and filter Add hot junction voltage to CJ compensation voltage Read cold junction CJ voltage END Start Convert voltage to temperature ...

Страница 45: ...to temperature This is done using the thermistor calculator component The component supports both LUT and the Steinhart Hart equa tion and provides an API for converting resistance to temperature Read Vssa Ref voltage for CDS Read voltage across thermistor Vt and perform offset cancellation CDS Calculate thermistor resistance from Vref and Vt Calculate temperature from the thermistor resistance Re...

Страница 46: ...s conversion The RTD component chooses the correct polynomial order based on your accuracy requirements Start Set IDAC to source 128 uA current End Connect IDAC current mux to calibration reference resistor and measure voltage V1 Read voltage across calibration resistor zero current for CDS CDS and filter V1 Connect IDAC current mux channel to RTD and measure voltage V2 Read voltage across RTD sen...

Страница 47: ...cribes the calibration details The calibration steps for the RTD are as follows 1 Scroll down to the Calibrate RTD eighth item in the menu using CapSense buttons Yes Yes Yes Get Vbe at 10 uA Get Vbe at 100 uA Get voltage difference and filter the difference Get zero current offset voltage Set IDAC current to 10 uA CDS voltage and filter as Vref1 Calculate the current ratio Calculate temperature fr...

Страница 48: ...on constant is calculated from the measured RTD resistance at the set temper ature and the expected temperature value entered by the user After calibration the LCD displays the message Calibrated Press SW2 CY8CKIT 030 or SW1 CY8CKIT 001 to go to the main menu temperature display Figure 5 12 RTD Calibration Note The calibration constant is used inside RTDRestoTemp for calibration On system reset th...

Страница 49: ...erature to a known measured value between 0 C and 100 C and enter that temperature using the CapSense slider and buttons Use the CapSense slider for coarse temperature setting and the CapSense button for fine settings P5_5 P0_5 to increment the tem perature in 0 1 C steps and P5_6 P0_6 to decrement the temperature in 0 1 C After the tem perature is entered accurately press the switch SW2 in CY8CKI...

Страница 50: ...asurement are as follows 1 Scroll down to the Calibrate IC eleventh item in the menu using CapSense buttons 2 Proceed through the calibration steps using mechanical switch SW2 connected to P6 1 of CY8CKIT 030 or SW1 connected to P1 7 of CY8CKIT 001 3 The LCD displays Set Temp Force the IC temperature to a known measured value between 0 C and 100 C and enter that temperature using the CapSense slid...

Страница 51: ...oltage of the sensor The filter for a sensor is selected in such a way that the temperature resolution of the sensor is 0 1 C The function FilterSignal in the code performs filter ing Applying a filter increases the temperature settling time A filter with a low cut off frequency takes a much larger time for the temperature to settle down To avoid large settling times when the tempera ture changes ...

Страница 52: ...ors and voltage inputs These measurements are in the following order diode tem perature IC temperature 3 3 V rail 5 V rail 20 mV full scale input and 100 mV full scale input P5_6 can be used to cycle through the measurements in reverse order In the previous example readings are only taken when the LCD displays that particular measure ment However in this project ADC readings are taken continuously...

Страница 53: ...hat 5 V is not accidentally driven on the pin if the system is set for 3 3 V 4 Connect a 20 mV full scale differential signal from a voltage to source P5_2 and P5_3 You can also use an analog output pressure sensor or load cell to give 0 20 mV input 5 Connect a 100 mV full scale differential signal from a voltage to source P1_6 and P1_7 You can also use an analog output pressure sensor or load cel...

Страница 54: ...ation chapter on page 18 5 3 2 1 2 CY8CKIT 001 PSoC DVK 1 Plug the PSoC Precision Analog Temperature Sensor EBK to port A of the CY8CKIT 001 DVK 2 In the pin header breadboard area of the CY8CKIT 001 base board use jumper wires to make the following connections a VR to P0_7 The VR is used as the 5 V input Ensure that the VR is turned to output 5 V The VR makes sure that 5 V is not accidentally dri...

Страница 55: ...2 2 Run Sequenced ADC Example Firmware 5 3 2 2 1 CY8CKIT 030 PSoC 3 DVK The steps to run the example firmware on CY8CKIT 030 are 1 Attach a USB cable from the PC to the PSoC 3 DVK program debug USB port use J1 the USB connector closest to the corner of the board 2 Open the SequencedADC_030_050 project using PSoC Creator and select Debug Program to program the PSoC 3 Detach the USB cable and connec...

Страница 56: ...s not optimized for analog routing 5 3 2 3 Testing the Project For best results when testing the temperature measurements ensure that you have good thermal contact between the sensor RTD diode or IC sensor and your reference thermometer 5 3 2 4 Expected Performance and Test Results This section provides details about the expected performance of the temperature voltage and power rail measurements T...

Страница 57: ...temperature A standard thermometer with 1 C accuracy is used for comparison 5 3 2 4 5 DS600 IC Temperature Sensor The DS600 typically is within 0 5 C Table 5 10 provides an example of measured temperature A standard thermometer with 1 C accuracy is used for comparison Note that as mentioned in DS600 IC Sensor on page 39 the IC measures the pad temperature below it and the IC signal chain is accura...

Страница 58: ... Hz or 60 Hz hum on each reading If the ADC readings are taken at consistent intervals then specific filters can be applied for each reading This project reads seven different inputs a 20 mV full scale voltage a 100 mV full scale voltage an RTD temperature sensor a diode temperature sensor a DS600 IC temperature sensor a 3 3 V volt age rail and a 5 V rail Some measurements such as RTD diode and IC...

Страница 59: ...conversion it triggers an interrupt ADC_INT c In this interrupt the IDAC8 CurrentMux ADCMux and ADC are changed to prepare the signal chain for the next mea surement Also the ADC readings are filtered in this ISR The filtered results are then stored in a ping pong buffer to be read later To ensure that the firmware in the ADC ISR executes before the next ADC SOC is triggered by the scheduler the c...

Страница 60: ...CY8CKIT 025 PSoC Precision Analog Temperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J 60 Example Projects Figure 5 15 Schematic for Input Muxes and IDAC ...

Страница 61: ... these different sensors four different ADC configurations are used The ADC configurations are switched in the ADC interrupt Table 5 12 shows the 15 ADC readings and their ADC voltage range Table 5 12 ADC Reading and Voltage Range Measurement ADC Reading ADC Input Range 20 mV Input 20 mV Input 0 064 V RTD RTD 0 256 V RTD CDS 0 256 V Reference Resistor 0 256 V Reference Resistor CDS 0 256 V 100 mV ...

Страница 62: ...ifferent ADC configurations Figure 5 16 0 064 V ADC Configuration Note that Buffer Mode is set to Level Shift because many of the voltages being read are near VSS this setting yields better ADC results for signals near VSS The sample rate of 3861 is chosen such that each sensor is read at a repeat rate of 110 Hz Figure 5 17 0 256 V ADC Configuration ...

Страница 63: ...18 1 024 V ADC Configuration Figure 5 19 6 144 V ADC Configuration Note that the Buffer Mode is set to Bypass Buffer because the voltage being read is near VDD this setting yields better ADC results for signals near VDD However the input impedance of the ADC is lower without the buffer so the input signal should not load the ADC ...

Страница 64: ...t ADC reading The ISR also filters the current ADC reading and stores the filtered result in a ping pong buffer to be read later Figure 5 20 shows the ADC ISR flowchart The ISR code is found in ADC_INT c This interrupt is triggered at the end of every ADC conversion Table 5 13 IDAC Range and Values Measurement ADC Reading IDAC Range IDAC Value RTD RTD 2 mA 1 024 mA RTD CDS 2 mA 1 024 mA Reference ...

Страница 65: ...valid Flag from last reading Does Current Slot HW Counter N Reset HW Counter Set Invalid Flag Y Get ADC Reading Result Increment Next Slot Next Slot of Slots Next Slot 0 Configure ADCMux for Next Slot Y N Configure IDAC Range Value and Mux for Next Slot ADC Reconfiguration Process ADC Reconfiguration Process ADC Config Valid Y Stop ADC Reconfigure It Restart ADC Clear next Invalid Set Next Invalid...

Страница 66: ...are scaled up by 1000 and then divided by ADC_COUNTS_PER_VOLT The result is in thousandths of a volt RTD and DS600 To avoid floating point math the conversion from ADC readings to temperature uses integer math To preserve precision the readings are scaled up Thus the final result of the temperature measure ments is in hundredths of a degree C For more information on the conversion see the inline c...

Страница 67: ...o current through the RTD diode or calibration resistor and measure the ADC out put across the RTD diode calibration resistor 5 3 3 3 5 Calibration For this project user calibration is not available for the temperature sensors The 3 3 V and 5 V mea surements are adjusted by a calibration factor This is because the ADC configuration 6 144 V ADC input range used to read the 3 3 V and 5 V rail is not...

Страница 68: ...h SW2 to cycle through the three menu items Zone 1 Summary Temperature algorithm used to compute zone temperature desired fan speed and actual fan speed Zone 2 Summary Temperature algorithm used to compute zone temperature desired fan speed and actual fan speed Temperature Sensor Summary The temperatures of the individual temperature sensors in each zone and the zone temperatures Figure 5 21 Therm...

Страница 69: ... are available at www cypress com go CY8CKIT 036 5 4 1 2 Using TME EBK with CY8CKIT 025 You can control the fans in the TME EBK using the temperature sensors in the CY8CKIT 025 EBK The TME EBK has only one analog temperature sensor which is the diode based temperature sen sor To illustrate the analog temperature sensing capabilities of PSoC 3 better the CY8CKIT 025 EBK is combined with the TME EBK...

Страница 70: ...CKIT 030 and CY8CKIT 050 are identical follow the instructions provided for CY8CKIT 030 PSoC 3 DVK for CY8CKIT 050 PSoC 5LP DVK as well except that PSoC 5LP device CY8C5868AXI LP035 should be selected Project Device selector The main difference between the examples for the CY8CKIT 001 and CY8CKIT 030 platforms is the PSoC pin mapping 5 4 2 1 1 CY8CKIT 030 PSoC 3 DVK 1 No jumper wires are required ...

Страница 71: ...ue to this pin sharing the TME EBK should not be attached to the CY8CKIT 030 DVK while programming the PSoC 3 device using MiniProg3 or DVKProg3 pro grammer After the programming is complete remove the programmer from the programming header on the PSoC 3 DVK and then attach the TME EBK to port D Due to pin sharing debugging the project is also not possible because it uses the same programming pins...

Страница 72: ...er Jumper 4 Ensure that the VR_PWR jumper J11 is installed Figure 5 29 CY8CKIT 001 PSoC DVK VR_POWER Jumper CAUTION The TME EBK plugged into port B of the CY8CKIT 001 DVK uses the SWD JTAG pro gramming pins for fan control as well Due to this pin sharing the TME EBK should not be attached to the PSoC DVK while programming the PSoC 3 device on the DVK using MiniProg3 programmer After the programmin...

Страница 73: ... RTD is used for temperature measurements Figure 5 30 CY8CKIT 025 RTD Jumper 2 Connect the diodes as shown in Figure 5 31 Figure 5 31 CY8CKIT 025 Diodes 5 4 2 1 4 CY8CKIT 036 Thermal Management EBK 1 Connect the fans to headers fan 3 and fan 4 as shown in Figure 5 32 Note that the fans are con nected to headers 1 and 2 by default Figure 5 32 Thermal Management EBK Fans 2 Configure jumper J9 to pow...

Страница 74: ...ower supply to the DVK as well 5 Connect the CY8CKIT 025 EBK and TME EBK to the DVK as shown in Figure 5 22 6 Power the PSoC 3 DVK and the TME EBK as shown in Figure 5 22 7 Press the Reset SW1 button on the PSoC 3 DVK to run the newly programmed firmware image 8 On reset the LCD displays a welcome message and starts with the Zone 1 temperature reading and the corresponding temperature calculation ...

Страница 75: ...eeds will match the corresponding zone thermal profiles Press the push button SW1 on CY8CKIT 001 or SW2 on CY8CKIT 030 once to view the characteristics of Zone 2 Press the push button SW1 on CY8CKIT 001 or SW2 on CY8CKIT 030 again to view the individual sensor temper atures for each zone and the weighted composite zone temperature Pressing the button again will repeat this display sequence 5 4 3 P...

Страница 76: ...00 C The Zone 1 speed transfer function is table driven and follows the profile shown in Figure 5 34 Figure 5 34 Thermal Management System Project Zone1 Thermal Profile Zone 2 corresponding to Fan 4 in Figure 5 35 consists of two temperature sensors and a single fan The Zone 2 speed transfer function is table driven and is shown in Figure 5 35 Note that the temper ature range is very narrow and cl...

Страница 77: ...sistor and potentiometer which simulates an analog temperature sensor IDAC is used to provide the excitation currents for the diode RTD and calibration resistor The closed loop fan con troller component senses and controls the fan speed Application notes AN60590 and AN70698 provide detailed explanations on temperature measure ment using diode and RTD respectively Application note AN66627 describes...

Страница 78: ... the hardware blocks inside PSoC without any CPU intervention See the FanController com ponent datasheet in PSoC Creator for details on the other parameters Figure 5 38 FanController Component Configuration Fans Tab This tab provides the option to choose the number of fans and the speed to RPM mapping of each fan The individual fan parameters are configured as shown in Figure 5 38 The configuratio...

Страница 79: ...voltage can vary from 0 to VDDA The Bypass Buf fer option is selected for the Buffer Mode parameter to measure voltage near the supply rails Figure 5 39 ADC Configuration for Potentiometer Voltage Measurement Figure 5 40 shows the ADC configuration to measure voltage across the sensors diode and RTD The Resolution parameter is set to 20 bits to perform high resolution temperature measurements Figu...

Страница 80: ...on the Test Application tab of the project schematic The thermal manager implementation is available in ThermalManager c and on the Thermal Manager tab of the project schematic The main application must call ThermalManager_Start to initialize the thermal manager Then it must periodically call ServiceThermalManager to run temperature and speed updates In this example this is done every 500 ms but c...

Страница 81: ...e temperature calculation algorithm used Line 2 displays the desired fan speed and the actual fan speed for Zone 1 Figure 5 43 Zone 1 Summary Screen 2 Zone 2 Summary This screen displays the current status of Zone 2 Line 1 displays the zone number current com posite zone temperature and the zone temperature calculation algorithm used Line 2 displays the desired fan speed and the actual fan speed f...

Страница 82: ...t temperature sensor readings for all sensors in the system Line 1 displays the Zone 1 temperature sensor values The temperature on the extreme left is the zone s composite temperature followed by the temperatures of each contributing sensor Line 2 displays the same information for Zone 2 Figure 5 45 Temperature Sensors Summary Z 2 T 2 6 W E I G H T E D F 4 7 0 0 0 A 4 7 0 6 2 Z 1 T 7 9 8 5 2 5 Z ...

Страница 83: ... SEMICONDUCTOR 2011 REF 15102 CY8CKIT 025 PSoC Precision Analog Temperature Sensor Expansion Board Kit A 1 1 Friday April 01 2011 Title Size Document Number Rev Date Sheet of CYPRESS SEMICONDUCTOR 2011 REF 15102 CY8CKIT 025 PSoC Precision Analog Temperature Sensor Expansion Board Kit A 1 1 Friday April 01 2011 Title Size Document Number Rev Date Sheet of CYPRESS SEMICONDUCTOR 2011 REF 15102 CY8CKI...

Страница 84: ...CY8CKIT 025 PSoC Precision Analog Temperature Sensor Expansion Board Kit Guide Doc 001 65791 Rev J 84 A 2 Board Layout A 2 1 PDC 09802 Top A 2 2 PDC 09802 Bottom ...

Страница 85: ...20E 1 RES 20 0 OHM 1 8W 1 0805 SMD Vishay Dale CRCW080520R0FKEA 9 1 RTD1 TEMP SENSOR RTD TEMP SENSOR RTD 100 OHM 0805 Vishay Beyschlag PTS080501B100RP100 10 1 R8 100E 0 1 RES 100 OHM 1 8W 0 1 0805 SMD Panasonic ECG ERA 6AEB101V 11 1 J6 2p_jumper CONN HEADER VERT SGL 2POS GOLD 3M 961102 6404 AR 12 2 R3 R4 0E Resistor RES 0 0 OHM 1 8W 0805 SMD Panasonic ECG ERJ 6GEY0R00V 13 1 U1 DS600U IC SENSOR TEM...

Страница 86: ... reflect support for PSoC5 E 03 28 13 VRNK Added the Safety section Updated images in the Code Exam ples chapter Minor updates throughout the document F 04 26 13 VRNK Updated CY8CKIT 001 PSoC DVK Thermistor Temperature on page 40 and CY8CKIT 030 PSoC DVK on page 53 G 09 12 13 SASH Updated images for PSoC Creator ECR Added section 5 1 1 H 04 07 14 RKAD Updated section 5 2 2 4 5 I 08 17 16 SRDS Upda...

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