Specifications

ManualsBrandsAdvantech ManualsComputer equipmentPCM-3350

Lab 1

Introduction to MATLAB xPC Toolbox and the Advantec PC 104 computer boards

Introduction

The PC104 standard is for a system of computers that are small in size, and stackable so that any

peripheral module with the same standard of size and number of pins can be interfaced to it. The systems

we will be using in the lab are made by Advantech. We have two different modules, the older PCM 3350

and the new PCM 3355L boards. They require low power and can be used for general purpose embedded

applications. You may read more about their specifications on their respective manuals uploaded on

blackboard.

In the lab each group will have access to two PC104 computers. They are installed with Diamond MM

A/D D/A boards and screw terminals that provide connections to them. In the first lab you will be

familiarizing yourselves with the various functionalities/capabilities of these embedded computer

systems. You will also learn how to use the MATLAB xPC Target toolbox for embedded systems

programming. For all experiments performed in this lab, we will design models in Simulink and then

utilize a C compiler to create executable code from the models. The code will then be ported to the flash

memory on the PC104 board and run from there.

By the end of this lab, you should be well informed and completely comfortable in utilizing the various

resources these PC104 systems have to offer. All the skills you learn in this lab will be required in future

labs for successful completion of the semester.

NOTE: The computer systems in GWC laboratory are such that they lose all information upon restart and

also at 12:00 am midnight. As such, it is strongly recommended to carry flash drives and save all your

work in it at all times. Also, MATLAB needs to be configured in a particular manner for use in this lab.

Since the computers reset, these configurations will have to be done every time you come in.

Setting up Matlab for first use

These procedures must be followed every time you come to the lab.

Step 1. Compiler configuration

NOTE: Throughout these lab manuals, type command or run command means you should enter the

command into the MATLAB main command window. MATLAB always has “>>” symbol to indicate

where your commands are entered. We use the same symbol in this manual to indicate it is a MATLAB

command. To see what licenses and toolboxes are installed in MATLAB you can type “ver” and hit enter.

At the very bottom you should see the xPC Target and xPC Target Embedded Option listed. Without

them you cannot do any work related to this lab.

Summary of content (19 pages)

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Lab 1 Introduction to MATLAB xPC Toolbox and the Advantec PC 104 computer boards Introduction The PC104 standard is for a system of computers that are small in size, and stackable so that any peripheral module with the same standard of size and number of pins can be interfaced to it. The systems we will be using in the lab are made by Advantech. We have two different modules, the older PCM 3350 and the new PCM 3355L boards. They require low power and can be used for general purpose embedded applications.
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Run command: >> xpcexplr The command opens the MATLAB xPC Target Explorer as shown above. This is the window that configures the xPC toolbox for embedded target programming. The first step is to configure the compiler that will convert our Simulink models into C code and eventually to executables. To do this, select “Compiler(s) Configuration” as shown in the image below. You will need to browse or type in the Compiler path.
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Make sure you click “Apply” every time, after making any changes. If you move to a different window without clicking “Apply”, the changes are not saved. Step 2. Target PC configuration xPC Explorer identifies each PC104 system as a target PC. By default the explorer will start with one target named TargetPC1. Each target PC can be programmed to run in either “Standalone” mode or in “DOS Loader” mode. We will look at each mode, their uses and how to configure them. Step 2.1.
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Step 2.2.a Serial communication using dos loader In xPC Explorer, go to TargetPC1> Configuration> Communication and under communication Protocol choose RS-232 (as shown in the figure). Choose the com port and baud rate you would like to set up on the target PC104. The Advantech PC104 has two serial ports (COM1 and COM2). Baudrate determines the speed, so choose the highest possible. Click “Apply”. Then go back to TargetPC1 > Configuration.
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TCP/IP uses IPv4 addressing schemes to communicate with different Ethernet devices. We will not go into a discussion about IPv4 addressing but enough to setup communications between the PC104 boards and the host computer. These are the following options to configure: Target PC IP address : the IP address labeled next to the PC104 board you are using (e.g 129.219.24.223) TCP/IP target port : 22222 LAN subnet mask address : 255.255.255.192 TCP/IP gateway address : 129.219.24.
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Step 2.3 Enabling secondary IDE Go to xPC Explorer, under TargetPC1> Configuration> Settings and enable “Enable Secondary IDE” (see figure above). This will allow you to store data on the CF card. This data can be anything starting from error messages, A/D readings, serial port inputs etc. Step 3 Model file Configuration This needs to be done for every real time model you build. However unlike the setup processes in step 1 and step 2, these configurations are local to individual files.
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NOTE: It is best practice to ensure sample times are exactly the same all over your model file unless you specifically need different sample rates in different blocks of your Simulink model. If you must use two or more different sample times, they must be integer multiples of what you specify as “Fixed step size”. Choose “Stop time” based on the amount of time you want to run the embedded program. For this lab, it will be a good practice to leave it at inf (infinite).
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Experiment 1.1 Building familiarity with xPC toolbox and executing real-time code in PC104. For your first task you will create a real-time program that produces a square wave with amplitude 1, a period of 2 seconds and sampling time 0.1 seconds. The output should be visible on the monitor connected to the PC 104 board. For the scope, use a 100 point window (load this model file into PC 104 board using Standalone and DOS Loader (RS232 and TCP/IP) modes). Show your TA what you have done after each step.
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Once the model file is ready, save it and press Ctrl+b to build it. Then copy the three files shown in the below figure into the flash disc. NOTE: The “Current Folder” tab in the MATLAB file explorer shows the active working directory of MATLAB. You must save all your model files in this folder or else MATLAB will not know where the file or its dependencies are. In the example below ExpMdl is the active folder.
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Once the DOS Loader files have been created and loaded on to the CF disc, insert it into the PC104 board’s CF flash slot and boot it up. When the board is ready, go to xPC Explorer. You should see a .dlm file with the name of the model you created (this will only happen if the current working folder in MATLAB is set to the one where you saved your model file). Right click on “TargetPC1” and click “connect”.
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Answer the following questions in your report. Q1. Describe briefly the capabilities of the PC104 board and the Diamond MM A/D, D/A board with mention about its important technical specifications like Processor, A/D range resolutions, serial communication etc. and its application in not more than 150 words. Q2. Give 5 examples of the practical applications where you can put PC104 boards to use? Q3. What complier did you use to create a standalone to run on PC104? Q4.
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The above model, when implemented on the PC104 board transmits a square pulse using the serial link. You will find RS-232 Mainboard Setup block in the library browser under xPC Target> RS232> Obsolete V 1.0. Configure this block as shown below. You will find RS-232 Mainboard Send block in the library browser under xPC Target> RS232> Obsolete V 1.0> Asynchronous. Configure this block as follows.
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NOTE: use the same COM ports in both RS232 Mainboard Setup and RS232 Mainboard Send block. If they are different, unexpected results may occur. The above model must be implemented on the second board to receive and display the square wave using the serial link. You will find the RS232 Mainboard receive block in the library browser under xPC Target> RS232> Obsolete V 1.0> Asynchronous. RS232 Mainboard setup and send block should be configured as shown below.
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You can find the MUX block under library browser Simulink->Signal routing Answer these questions in your report. Q6. What is the fastest sampling time with 9600 baud in experiment 1.3 that the boards can tolerate? Why is there a limit? Q7. What is the delay from data goes from one serial port to another with the sampling time of 0.1 Q8. Change the sampling time to 0.01s and measure the delay again? What is the relationship between delay and sampling time? The final part of Exp 1.
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Use anything as Name of the connection and click ok. Make sure you choose COM1 and click ok. The host PCs in the lab only have one COM port. Set COM1 properties as above. This configuration has to match with the serial configuration in the simulation. If everything was setup correctly you should see the hyperterminal window printing out C=1.00 R=1.00 in every line. Type C0.34 and r-.25. You should see the value of R and C change, both on the target monitor and hyperterminal on the host PC.
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This is Part B of Lab 1. You will need to submit a separate report for this section. Experiment 1.4 Getting familiar with Diamond MM A/D and D/A boards. Before building any blocks we need to get familiar with the diamond MM board and its functionalities. The Diamond MM boards are a multifunction analog and digital I/O module compatible with the PC104 standard. It offers 16 single-ended or 8differential, bipolar analog inputs (A/D) with 12 bit resolution.
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This experiment, as you see is similar to exp 1.3; although, here you are using the D/A and A/D modules to transmit and receive the signal. Remember, that the D/A cannot transmit negative voltages. Connect the ports you configured in the blocks with their corresponding pins on the screw terminal using wires supplied to you in the lab. You should be able to see the waveform on the monitor. In the second part of this experiment, you will determine the delay in A/D conversion.
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To transfer the data from the CF card to MATLAB workspace, first right click on target PC in xPC Explorer and select it as default. Type the following commands (it will be advantageous to save these lines of code as a MATLAB script file) % Create file system object fsys = xpctarget.fs % Open file on the target file system h = fsys.fopen(‘DATA.DAT’) % Read the data from the target file into a MATLAB variable. Note that % this data will still be represented in xPC Target file % format (i.e.
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Q11 Do you notice anything wrong with the signal received through A/D? If so what do you think causes discrepancy in the signal? Q12 If diamond MM board is used in a feedback control loop will there be any phase lead/lag introduced to the loop due to D/A/A/D? Q13 Since the D/A in the diamond board does not output negative voltages.