CN0336软件用户指南

2079478 2021-04-09 | pdf | 1.13 MB | 次下载 | 3积分

资料介绍

This version (06 Jan 2021 08:43) was approved by Ioana Chelaru.The Previously approved version (06 Jan 2021 08:41) is available.

CN0336 Software User Guide

CN0336 Software User Guide

Overview

CN0336 provides robust and complete solution for 4 mA-to-20 mA current to digital conversion with isolation, for wide variety measurements where, sensors with standard 4-20 mA output are used. The design solution is optimized for high precision and low cost measurement, using only three active devices, and has a total unadjusted error of less than 0.1% of full scale range. The accuracy depends on the calibration. The circuit shown in Figure 1 incorporates AD8606ARZ OpAmp, AD7091RBRMZ 12-bit successive approximation (SAR) ADC, and ADuM5401ARWZ isolator to create a standard 4 mA-to-20mA current measurement system. The circuit has 12 pin PMOD connector on board, which could be used for connection to a customer microprocessor or FPGA. This CN0336 circuit note discusses the design steps needed to optimize the circuit shown in Figure 1 for a specific bandwidth including noise analysis and component selection considerations.

The performance of the circuit could be demonstrated with the use of Analog Devices SDP controller EVAL-SDP-CB1Z and SDP-to-PMOD Interposer Board SDP-PMD-IB1Z, both optional purchase items. This user guide will discuss how to use the evaluation software to collect data from the EVAL-CN0336-PMDZ Evaluation Board CN0336

Figure 1. 4 mA to 20 mA Single Supply Analog to Digital Conversion with Isolation (All Connections and Decoupling Not Shown)

Required Equipment

EVAL-SDP-CB1Z Controller Board (SDP-B Board)
EVAL-CN0336-PMDZ Evaluation Board (CN-0336 Board)
EVAL-CFTL-6V-PWRZ (+6V Power Supply) or equivalent
SDP-PMD-IB1Z SDP-to-PMOD interposer board
Current Calibrator
Multimeter(to measure the input current)
CN0336 Evaluation Software
- (supplied with provided CD in kit)
PC with the following Minimum Requirements
- Windows XP Service Pack 2 (32-bit)
- USB type A Port
- Processor rated at 1GHz or faster
- 512 MB RAM and 500 MB available hard disk space
USB type A to USB type mini-B cable

General Setup

The EVAL-CFTL-6V-PWRZ (+6V DC Power Supply) powers the EVAL-CN0336-PMDZ (CN0336 Board) via the DC barrel jack.
The SDP-PMD-IB1Z (Interposer Board) connects to the EVAL-SDP-CB1Z (SDP-B Board) via the 120-Pin connector A.
The EVAL-SDP-CB1Z (SDP-B Board) connects to the PC via the USB cable.
The EVAL-CN0336-SDPZ (CN0336) connects to the EVAL-PMD-IB1Z (Interposer board) via the 12-Pin header PMOD connector (J1 and J3)
The 4-20 mA current source (Current calibrator) connects to the EVAL-CN0336-SDPZ (CN0336 Board) via the terminal block J2

Installing the Software

Load the evaluation software by placing the CN0336 evaluation software disc in the CD drive of the PC. You can also download the most up to date copy of the evaluation software from www.analog.com/CN0336. Open the file setup.exe.

NOTE: It is recommended that you install the CN0336 Evaluation Software to the default directory path C:/Program Files/Analog Devices/CN0336/ and all National Instruments products to C:/Program Files/National Instruments/
Click Next to view the installation review page
Click Next to start the installation
Upon completion of the installation of the CN0336 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.

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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:/C:/Program Files/Analog Devices/SDP/DriversR2
Press “Next” to install the SDP Drivers and complete the installation of all software. Click “Finish” when done.

Connecting the Hardware

Connect the +6V DC Power Supply (Wallwart) to the barrel jack J1 of the Interposer Board (Interposer Board ) as depicted below.

NOTE: Make sure that the jumper is positioned as shown below!
Connect the 120-pin connector on the SDP-PMD-IB1Z (Interposer Board) to the 120-pin connector marked “CON A” on the EVAL-SDP-CB1Z (SDP-B Board)
Connect the USB cable supplied with EVAL-SDP-CB1Z (SDP-B Board) to the USB port on the PC and the SDP Board

NOTE: Verify that the SDP Drivers are loaded properly. For that purpose open the Device manager and check if the SDP Board is recognized. If not repeat steps 1-3

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Connect the EVAL-CN0336-PMDZ (CN0336 Board) to the SDP-PMD-IB1Z (Interposer Board) via the 12 pin header PMOD connector.
Connect the input current source (Current calibrator) to J2 Terminal Block. The polarity is shown on the picture below

Using the Evaluation Software

Software Control and Indicator Descriptions

Connect/Reconnect Button
- When this button is pressed, the SDP-B Board makes a USB connection to the CN0336 Board. A connection to the SDP-B Board must be made to use the software.
Run Button
- When this button is pressed, the SDP-B Board will collect conversion data and present the acquisitions in the chart.
Stop Button
- When this button is pressed, the software stop collecting data from the CN0336 Board
Clear Data Button
- When this button is pressed, the software will clear all data collected from the chart history.
Save Data Button
- When this button is pressed, the software will save the data collected to a tab delimited ASCII spreadsheet file.
Control Tabs
- Acquire DataMain - Clicking this tab brings the data collection graph to the front.
- Calibrate System - Clicking this tab brings the system calibration settings to the front.
- SDP Revision - Clicking this tab brings the SDP board information window to the front.
Numerical Indicator
- This indicator displays the current reading value. The value units depend on the chosen graph units (10).
Graph
- This graph displays the collected data. The units on the graph depend on the chosen graph units (10).
Graph Controls
- These controls allow the user to zoon in, zoom out, and pan through the data collected.
Graph Units Radio Buttons
- This control determines the units of the data displayed in the chart and the numerical indicator.
System Status String Indicator
- This indicator displays a message to the user detailing the current state of the software.
System Status LED Indicator
- This indicator displays the current state of the software in the form of an LED. There are four status LED colors.
  Inactive
  Busy
  Error
  Waiting for user action
Calibrate System Controls
- These controls allow the user to calibrate the CN0336 Board. For the calibration two current inputs in the range 4-20mA are required. For best performance the inputs have to be selected “4mA” and “20mA”. To perform the calibration follow the instructions on the screen.
SDP Firmware Revision
- Read only data. After the connection is established with the SDP Board, the basic information for the controller can be found here.

Establishing a USB Connection Link

Follow the instructions to properly install the software and connect the hardware as described in the previous sections.
Open the file named CN0336.exe in the installation directory.

NOTE: If the software was installed to the default location it will be found at
C:/Program Files/Analog Devices/CN0336/CN03366.exe
Click the Connect/Reconnect Button. A window with a progress bar will load.
Upon success, the System Status String Indicator will display SDP Board Ready to Acquire Data

Calibrating the CN0336 Board

Establish a USB Connection Link.
Click the Calibrate System tab.
Apply first calibration current to the input connector J2 of CN0336.
Write down the applied current to Calibration Current 1 indicator.
Press Calibrate 1 button.
Apply second calibration current to the input connector J2 of CN0336 and different from the previous calibration current.
Write down the applied current to Calibration Current 2 indicator.
Press Calibrate 2 button.