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This version (31 Jul 2015 11:49) was approved by JB.Chua, StevenX.

CN0376 Evaluation Board Guide

Overview

CN0376 is a dual-channel, channel-to-channel isolated, thermocouple or RTD input suitable for programmable logic controllers (PLC) and distributed control systems (DCS). Each channel can accept either a thermocouple or a RTD input. The entire circuit is powered from a standard 24 V bus supply.

The AD7124-4 24-bit, Σ-Δ ADC with programmable gain array (PGA) and voltage reference provides the complete set of features to implement a flexible input capable of connection to either thermocouple or RTD sensors. Features include on-chip reference, PGA, excitation currents, bias voltage generator, and flexible filtering with enhanced 50 Hz and 60 Hz rejection options. The AD7124-4 is in a small 5 mm × 5 mm LFCSP package, making it ideal in channel-to-channel isolated designs where space is a premium. It also includes multiple diagnostic functions that are available to the user. The ADuM5010 isolated dc-to-dc converter provides 3.3 V isolated power via integrated isoPower® technology. The ADuM1441 isolates the serial peripheral interface (SPI) for the AD7124-4. The ADuM1441 micropower isolator consumes only 4.8 µA per channel when idle, resulting in an energy efficient solution. The ADP2441 36 V, step-down, dc-to-dc regulator accepts an industrial standard 24 V supply, with wide tolerance on the input voltage and steps it down to 5V to be used by the system.

THe EVAL-CN0376-SDPZ evaluation connects to ADI's System Demonstration Platform(SDP) and also features PMOD-compatible headers for interfacing with other development platforms.


Required Equipment

  • EVAL-SDP-CB1Z Controller Board (SDP-B Board)
  • DC Power Supply (+12V to +24V)
  • RTD (PT100 or PT1000)
  • Thermocouple
  • PC with the following Minimum Requirements
    • Windows Vista/7 (32-bit)
    • USB type A Port
    • Processor rated at 1GHz or faster
    • 1GB RAM and 500 MB available hard disk space
  • USB type A to USB type mini-B cable

General Setup

  • The EVAL-CN0376-SDPZ (CN-0376 Board) connects to the EVAL-SDP-CB1Z (SDP-B Board) via the 120-Pin connector
  • The EVAL-SDP-CB1Z (SDP-B Board) connects to the PC via the USB cable.
  • Header P4 is a PMOD compatible SPI header for communication to Channel 1
  • Header P5 is a PMOD compatible SPI header for communication to Channel 2
  • Header PWR_SEL is used for selecting the power source of the system using a jumper (Terminal Block P3 or PMOD)
  • Terminal block P3 is the power supply input (input range:+5.5V to +36V DC)
  • Terminal block P1 is the sensor input (RTD or Thermocouple) for Channel 1
  • Terminal block P2 is the sensor input (RTD or Thermocouple) for Channel 2

Sensor Connection

2-Wire RTD

  • Connect RTD to AIN+ and AIN- terminals
  • Short terminals IEXC and AIN+
  • Short terminals RETURN and AIN-

3-Wire RTD

  • Connect RTD wires to AIN+, AIN- and RETURN termnials
  • Short terminals IEXC and AIN+

4-Wire RTD

  • Connect RTD to IEXC, AIN+, AIN- and RETURN terminals

Thermocoupe

  • Connect Thermocouple to AIN+ and AIN- terminals


Power Options

Jumper Positon EXT

  • System is powered using termnial block P3 (input range:+5.5V to +36V DC)
  • When no supply is present on P3, the system draws power from USB when using the SDP

Jumper Positon PMOD

  • System is powered using the PMOD headers (+3.3V DC)

Installing the Evaluation Software

  1. Extract the file CN0376_Evaluation_Software.zip and open the file setup.exe.

    NOTE: It is recommended that you install the CN-0376 Evaluation Software to the default directory path C:\Program Files\Analog Devices\CN0376\ and all National Instruments products to C:\Program Files\National Instruments\






  2. Click Next to view the installation review page

    {{:resources:eval:user-guides:circuits-from-the-lab:cn0364:install4.png?nolink&|}}

  3. Click Next to start the installation

  4. Upon completion of the installation of the CN-0376 Evaluation Software, the installer for the ADI SDP Drivers will execute.

    NOTE: It is recommended that you close all other applications before clicking “Next”. This will make it possible to update relevant system files without having to reboot your computer.





  5. Press “Next” to set the installation location for the SDP Drivers.

    It is recommended that you install the drivers to the default directory path
    C:\Program Files\Analog Devices\SDP\Drivers



  6. Press “Next” to install the SDP Drivers and complete the installation of all software. Click “Finish” when done.


Using the Evaluation Software

Software Control and Indicator Descriptions

Main Tab

  1. Run/Stop
    • Start/Stop data acquisition from the evaluation board
  2. Clear Data
    • Clear the data on the chart and on voltage/current indicators
  3. Save Data
    • Save the data collected to a tab delimited ASCII spreadsheet file
  4. Reset
    • Reset the evaluation board and software to the defualt startup configuration
  5. Channel 1 Temperature Display
    • Displays the temperature reading from Channel 1 ( in Degrees Celsius)
  6. Channel 1 RTD Resistance/TC Voltage Display
    • Displays the equivalent RTD Resistance of Channel 1 when in RTD Mode
    • Displays the Thermocouple voltage of Channel 1 when in Thermocouple Mode
  7. Channel 2 Temperature Display
    • Displays the temperature reading from Channel 2 ( in Degrees Celsius)
  8. Channel 2 RTD Resistance/TC Voltage Display
    • Displays the equivalent RTD Resistance of Channel 2 when in RTD Mode
    • Displays the Thermocouple voltage of Channel 2 when in Thermocouple Mode
  9. Cold Junction Compensation Information
    • Displays the Temperature and Resistance of the CJC Thermistor of both Channel 1 and 2 when in Thermocouple Mode
  10. Display Units
    • Temperature- data on the chart is displayed as degrees Celsius
    • ADC Code - data on the chart is displayed as ADC codes
  11. Chart
    • Data plot for the data acquisition (may be displayed as voltage/current value or ADC code)
  12. Status Bar
    • Displays a message to the user detailing the current state of the software There are three status LED colors:
      Inactive
      Busy
      Error

Histogram Tab

User needs to sample data first using Run to get histogram data on this page.







  1. Select Channel
    • Channel selection for Histogram display
  2. Get Histogram
    • Analyzes the data from the selected channel and displays the histogram data
  3. Maximum Code
    • Display for the highest code from the sampled data of the selected channel
  4. Minimum Code
    • Display for the lowest code from the sampled data of the selected channel
  5. Code Spread
    • Display for the difference between the highest and lowest code from the sampled data of the selected channel
  6. Peak-to-Peak Resolution
    • Display for computed Peak-to-Peak Resolution(bits) of the selected channel
  7. Histogram Graph
    • Plot for the histogram data

Configuration Tab

Allows for ADC configuration of either channel

Input Type

  • PT100 - activates the Excitation current source and configures the ADC to read from PT100 RTD
  • PT1000 - activates the Excitation current source and configures the ADC to read from PT1000 RTD
  • Thermocouple - activates the TC bias,CJC, and configures the ADC to read from thermocouple

RTD Connection

  • 2-Wire - Excitation current available at IEXC pin. Short IEXC and AIN+ pins. Short AIN- and RETURN pins.
  • 3-Wire - Matched Excitation currents available at IEXC and AIN- pins
  • 4-Wire - Excitation current available at IEXC pin. Short IEXC and AIN+ pins.

Power Mode - Select Power Mode of the ADC. This affects power consumption and ADC data rate. Please consult [ADI>AD7124-4] datasheet for more information

Filter Type - Select the digital filter used for the ADC conversion. Please consult [ADI>AD7124-4] datasheet for more information

Post Filter - Select the data rate when the Post Filter are used

Sampling Rate - Slider control to change the ADC data rate. The numerical display shows the corresponding data rate. This is dependent on the power mode and filter type

Enabled/Disabled - Toggle to enable or disable the corresponding channel

Configure - Press this button to apply the configurations to the corresponding channel

Advanced Configuration Tab

Allows control of Excitation Current, Burnout Current, PGA Gain and for enabling ADC Error Checks

Error Flags Tab

ADC Error Indicators. Please consult [ADI>AD7124-4] datasheet for information regarding the ADC Errors

Running the System

  1. Open the CN0376.exe application from the default installation location.
  2. The software will connect to the board automatically.
  3. Click the Run Button
  4. Click the Stop Button when acquisition is complete.

Saving Data to a Spreadsheet File

  1. Click the Save Data Button.
  2. Browse to the directory location where the spreadsheet file is to be saved.
  3. Name the file.
  4. Click the OK Button.


The software saves the spreadsheet file as ASCII text with columns separated by tabs


resources/eval/user-guides/circuits-from-the-lab/cn0376.txt · Last modified: 31 Jul 2015 09:54 by JB.Chua