PiXtend with CODESYS Create Project

Transcription

1 Creating a new CODESYS Project Adding PiXtend as a CODESYS Device Creating a simple Test Program Creating a simple Web Visualization Date 13/02/2018, V1.03 Qube Solutions UG (haftungsbeschränkt) Arbachtalstr. 6, Eningen, GERMANY / 28

2 Table of Contents 1. Introduction General Notes Copyright of Text and Pictures: Warning Applications for PiXtend Disclaimer Prerequisites Step by Step to the first PiXtend CODESYS program Create a CODESYS standard project for PiXtend Add SPI Device Add PiXtend Device Create Global Variable List Mapping of Variables Task Configuration Main Program PLC_PRG Connecting to the PiXtend and performing a program download Further Steps Creating the CODESYS Webvisu / 28

3 1. Introduction This manual describes all necessary steps to create a new PiXtend Project in CODESYS. You will learn how to use the PiXtend () as a CODESYS ( device, and how to create a simple visualization for your project. The following three main software components will be used: CODESYS is the leading hardware-independent IEC automation software for developing and engineering controller applications. It is developed and maintained by the company 3S-Smart Software Solutions in Kempten, GERMANY To program a Raspberry Pi using CODESYS, a special Raspberry Runtime Extension for CODESYS is required. The Raspberry Pi Runtime Extension is also developed by the company 3SSmart Software Solutions in Kempten, GERMANY In order to gain direct access to the I/O Hardware and interfaces on the PiXtend Board from CODESYS, the PiXtend for CODESYS device drivers are required. The device drivers are provided by the company Qube Solutions UG (limited liability), Eningen, GERMANY This manual assumes that the three software components have already been installed correctly. If you have not installed them yet, please refer to the Application Note PiXtend with CODESYS Installation on how to do so. 3 / 28

4 1.1 General Notes Copyright of Text and Pictures: Text and pictures marked with "(3S)" belong to 3S-Smart Systems GmbH in Kempten, Germany Text and pictures marked with "(RPI)" belong to the Raspberry Pi Foundation Text and pictures which are not marked, or marked with "(QS)" belong to Qube Solutions UG in Eningen, Germany Warning PiXtend must not be used in safety critical systems. Check prior to use the suitability of Raspberry Pi and PiXtend for your application and environment Applications for PiXtend The PiXtend can be used for private and commercial projects, such as: Home Automation, Smart Home Evaluation of sub-systems, Proof of Concept, pre-series, series Learning and Teaching platform for control systems and automation Learning and Teaching platform for microcontroller hard- and software techniques HAM-Radio, DIY and Maker Applications 1.2 Disclaimer Qube Solutions UG and 3S-Smart Software Solutions can not be held responsible for any potential harm or damage to software, hardware, equipment or connected components, caused by the usage of provided software, drivers or hardware products. 4 / 28

5 2. Prerequisites This manual assumes that you have read the Application Note PiXtend with CODESYS Installation and that the three components CODESYS, CODESYS Control for Raspberry Pi, and PiXtend for CODESYS have been successfully installed. For hard- and software requirements please refer to the Application Note PiXtend with CODESYS Installation. 5 / 28

6 3. Step by Step to the first PiXtend CODESYS program 3.1 Create a CODESYS standard project for PiXtend Start the CODESYS Environment. Create a new Project by clicking on Main Menu File New Project (Shortcut Ctrl-N). Select "Standard project" from the category "Projects", choose a project name and location (here "D:\Projects\PiXtendTest") and press OK. Select "CODESYS Control for Raspberry Pi" as the device, and select "Continuous Function Chart (CFC)" as the program language for the main program PLC_PRG. 6 / 28

7 You will now see blank CODESYS standard project with the following structure: 7 / 28

8 3.2 Add SPI Device In the project tree, right click on the SPI item and select Add Device : 8 / 28

9 Select "SPI master" and click the Button "Add Device". Please leave the window opened. In the project tree a new SPI sub entry was created, named "SPI_master (SPI Master)". 9 / 28

10 3.3 Add PiXtend Device While the Add Device Pop-up is still open, please select the newly created SPI Master by clicking on it in the project tree. The contents of the Add Device Pop-up will now be updated. In the vendor drop-down please select the entry Qube Solutions UG", and select the Device "PiXtend" (not PiXtend_DAC). Click on the Add Device button and finally the Close button. Now you can see that the PiXtend appears as a device under "SPI_master (SPI Master)". 10 / 28

11 A double click onto PiXtend in the device tree will open the configuration section for the device. In the tab SPI devices I/O Mapping you can see which inputs and outputs of the PiXtend are accessible from CODESYS. In order for the process image being exchanged periodically, you will have to make two changes here: Please select "Enabled 1 (use bus cycle task if not used in any task) and for the bus cycle task select Main Task. At a later point when you are online to the controller, you could come back to this tab to monitor the process image of the PiXtend. You will be able to see input values changing, and you can force output values for testing purposes. We will need access to some of these values from our main program and the visualization. Therefore we are now going to create a Global Variable List (GVL) and assign inputs and outputs to variables. 11 / 28

12 3.4 Create Global Variable List In the project tree perform a right-click on "Application", click Add Object and add a Global Variable List with the name "GVL": Now open the GVL and add the following code: //Digital Inputs xdi0: BOOL; xdi1: BOOL; //Digital Outputs xdo0: BOOL; xdo1: BOOL; //Status byucstatus: BYTE; byucversionl: BYTE; byucversionh: BYTE; //Control byuccontrol: BYTE; 12 / 28

13 To keep this manual simple, we limit ourselves to only use 2 digital inputs and 2 digital outputs for now. xdi0 is the variable name for our the first digital input (input 0) xdo0 is the variable name for the first digital output (output 0) Please notice the difference between O (letter) and 0 (number). Prefixing variable names with their type is very useful, especially in bigger projects. We suggest to use x as a prefix for BOOLean variables (1 or 0) instead of b, to avoid confusion with variables of type BYTE (Prefix by). More prefixes we use: x by w dw r s BOOL BYTE WORD DWORD REAL STRING 13 / 28

14 The byte byuccontrol is required to put the microcontroller into run mode, which enables the data exchange between the microcontroller on the PiXtend Board and CODESYS. The byte byucstatus can be used to determine in which state the microcontroller is. The two bytes byucversionh and byucversionl hold the current software version of the microcontroller firmware. Of course you have total control over the naming of the variables used in the GVL, but in this manual we will stick with the same naming conventions as used in the PiXtend Demo Project to keep it simple. 3.5 Mapping of Variables Now that we have created the required variables in the GVL, we will have to map them, which means assigning them to their respective PiXtend hardware in- and outputs. Therefore please open the already familiar tab "SPI devices I/O mapping" by double clicking the PiXtend device. 14 / 28

15 Expand the "Digital In" section, and also the Channel DigIn. Now we can bitwise map the newly created GVL variables to the PiXtend's digital Inputs: Double-click into an empty row and three dots ( ) will appear. Clicking on the three dots will open the input assistant, where we can now select the desired variable. Please select the variable Application GVL xdi0 for DigIn Bit0: 15 / 28

16 Repeat this process for the remaining variables: Application GVL xdi0 for Digital In DigIn Bit0 Application GVL xdi1 for Digital In DigIn Bit1 Application GVL xdo0 for Digital Out DigOut Bit0 Application GVL xdi1 for Digital Out DigOut Bit1 The mapping of control and status bytes can be done in the same way: Application->GVL->byUCControl for Control->CtrlUC Application->GVL->byUCStatus for Status->ucStatus Application->GVL->byUCVersionL for Status->ucVersionL Application->GVL->byUCVersionH for Status->ucVersionH 16 / 28

17 Finally the GPIO24 Bit of the Raspberry has to be configured as an output. Open the Raspberry Pi GPIO configuration tab by double-clicking onto GPIOs_A_B in the project tree. On the GPIO Parameters tab change to Output for GPIO24. After that please switch to the tab GPIOs I/O Mapping and assign rpi_gpio24 for Output Bit 24: 17 / 28

18 3.6. Task Configuration In contrast to sequential programs (i.e. like C or PHP) which generally get executed only once (from top to bottom), programs used in PLCs (Programmable Logic Controllers) generally get executed periodically in fixed intervals, where first inputs are read, then the program logic gets evaluated, and finally the outputs are set. A so called task is used to determine which programs to execute when. One can specify the order and the interval of program calls. The typical actions that are performed within one PLC cycle are: get all input states and store them temporarily execute program logic to calculate new output values assign all output values To change the settings for the MainTask, double-click Task Configuration MainTask and change the cycle time to t#100ms. The minimum cycle time depends on the used hardware. By choosing 100 ms as the cycle time, the PiXtend has plenty of time to perform all operations in time. The special notation t#... is used for time values and is specified in IEC The MainTask will now get executed every 100ms and the program PLC_PRG will be called. 18 / 28

19 Note: If no DHT11/22 sensors are connected and used with PiXtend, the cycle time (bus cycle) can be reduced to 25 ms (for the device "PiXtend"). This can especially be interesting when rapid control (closed loop) is to be realized. Each DHT11/22 sensor extends the minimum cycle time (the "PiXtend" device) to about ms. However, the device "PiXtend_DAC" can operate with a cycle time of 1 ms. It is then advisable but to create a separate task for the DAC. 3.7 Main Program PLC_PRG Now it is time to create the actual program PLC_PRG. We want to monitor the state of the two inputs DI0 and DI1 and control the two outputs DO0 and DO1 according to some simple logic. The actual program logic can be described using a variety of different programming languages. The language LD (Ladder Logic Diagram) looks more like an electrical diagram with contacts and coils rather than a textual programming language. Other languages like ST(Structured Text) and IL (Instruction List) are textual. ST can probably be best described as a mixture of BASIC and PASCAL with a few features known from C. While IL is mainly chosen for speed critical operations it can be a bit hard to read as it is similar to assembly language. For the main program "PLC_PRG" we already chose to use "Continuous Function Chart" when we created the CODESYS Project at the beginning of this manual. CFC (Continuous Function Chart) is a graphical programming language. Complex PLC programs are usually organized in several different POUs (Program Organization Units) which makes the code easier to understand and to maintain. We only use one POU for now, which is the CODESYS default main program PLC_PRG. Double Click PLC_PRG in the project tree to bring up the editor. For a start, please drag four Input blocks blocks from the toolbox and drop them into the workspace. 19 / 28

20 Repeat this with four Output blocks and connect each input block with an output block, by dragging a connection line from the input block to the output block. Click in the centre of a block to assign a variable or constant, as shown below. A click on the three dots ( ) will bring up the Input Assistant. You can either type in the variable name, use auto completion (Ctrl-Spacebar), or select from Input Assistant. 20 / 28

21 Once you have assigned the variables and constants as shown above, you have already created your first functional program. Here is a short explanation: The constant number 16 is permanently written to the Byte byuccontrol, which makes the PiXtend microcontroller to enter Run-Mode. The Raspberry Pi Pin GPIO24 is permanently set to TRUE, which is required to enable the SPI communication with the PiXtend microcontroller The state of input xdi0 is written directly to output xdo0. The value of input xdi1 is written directly to output xdo1. Why 16? Because Bit5 of the byte byuccontrol is the RunMode bit. Instead of a decimal 16 you could also use 2# , which is the binary representation of 16. To improve readability one could also use a score as a separator: 2#0001_0000. If you prefer hexadecimal notation, you could use 16#10 instead. The result is always the same, no matter if you use 16, 2#0001_0000 or 16#10. More detailed information about the Control and Status Bytes can be found in a separate application note. To build the project please click Build->Build in the main menu bar. 3.8 Connecting to the PiXtend and performing a program download Once the program compiles without errors, double-click on "Device (CODESYS Control for Raspberry)" in the project tree and then click the Scan Network button. 21 / 28

22 CODESYS now searches the local network for a Raspberry Pi with the CODESYS Raspberry Pi Runtime on it. If your device does not appear here, please check the following things: Are you using the correct SD Card Image which has the CODESYS Runtime Extension installed on it? You can download a preconfigured PiXtend CODESYS Image from our download section (/downloads). To create your own CODESYS Image please refer to the manual included in the CODESYS Control for Raspberry Pi package provided by 3S. Is the Raspberry Pi powered on? Did it obtain a valid IP, which you can ping from your local machine? (via ping from the windows command line) If you don't know the IP, you can use the command ifconfig from the Raspberry Pi command line. If you can see a valid IP here, but you are not able to ping it, check your network connections to the Raspberry Pi. Notice: if the Raspberry Pi has been powered up for more than 2 hours, the CODESYS Runtime Extension stops working, unless you have licensed it. After a reboot (sudo shutdown -r now) it will work for another 2 hours. If the Raspberry Pi appears in the list, please select it and click Online Login in the main menu bar to go online and perform a download of the program. 22 / 28

23 As soon as you are online, you can hit F5 to switch the PLC into RUN-Mode and monitor the live values in the PiXtend I/O Mapping section. Double-click on PiXtend in the project tree and bring up the tab SPI Devices I/O Mapping. Under Status "ucversion_low" and "ucversion_high" you can see the version of the microcontroller: This is a PiXtend V1.2 Board (ucversion_high = 12) and to the microcontroller version 4 (ucversion_low = 4). If you own a PiXtend V1.3, the versions are correspondingly different. The channel ucstatus should be in normal operations a "1". This means that the microcontroller on PiXtend in in "Run Mode". Notice: The shown values for the microcontroller and PiXtend board version are just an example to illustrate the function of the Status-Bytes. 23 / 28

24 3.9 Further Steps Test the functions of your program by applying a HIGH level to the PiXtend digital input0 / input1 and see what happens at output0 / output1. Please consult the PiXtend technical data sheets first if you are not sure about how to connect it. Once you have understood the basics, you can modify the PLC_PRG to your likings. You could for example try the following: Go offline and add another block from the toolbox. Make it an AND-Block by clicking on the three question marks (???) and typing in AND. Connect one input of the AND-Block with xdi0 and the other one with xdi1. Now the Output of the AND Block will only become TRUE if both of the Inputs are TRUE at the same time. Test again. To make it a bit more interesting, you could add an additional timer block. Drag in a new Block and make it a TON block (on-delay). Also assign it an instance name (here timer_delay"). Drag in a new Input block and enter the constant time t#2s. Now connect it's output to the PT Input of the TON-Block. Connect the timer's IN Signal with the output of the AND-Block. Connect the Q output with xdo1. Go online and test again. You will notice that xdo1 only comes on once both Inputs (xdi0 and xdi1) have been HIGH for 2 seconds or longer. 24 / 28

25 4. Creating the CODESYS Webvisu Now we want to add a simple visualization for our project, so that we can observe our controller from any PC or Smartphone / Tablet on the network. To add a visualization, right-click on Application Add Object Visualization in the project tree. CODESYS now automatically adds the "Visualization-Manager" and a new "Visualization" Object. The manager can be used to change visualization properties, like the default visualization, update rate, URL, etc.. We don't need to change anything here. 25 / 28

26 To open the visualization editor, please double-click the "Visualization" object in the project tree. CODESYS comes with a bunch of predefined controls which we can be used out of the box. Open the toolbox, select Lamps/Switches/Bitmaps and drag four lamps into the workspace. Add four labels and assign the respective variable name to the lamps Variable property (xdi0, xdi1, xdo0, xdo1). 26 / 28

27 As labels are always static, we will use text fields to display a variable value. Drag two new text fields into the workspace and enter for each %d" as the "Text" Property. This will create a place-holder for an integer variable. Tick the Expert checkbox and add "byucversionh" and "byucversionl" respectivly to the Text variable property. At runtime, the two placeholders %d will be filled with the content of the two variables byucversionh and byucversionl. Other placeholders that can be used are i.e. %s for strings, or %f for floats (REAL, LREAL). Formatting parameters as known from C are also possible. 27 / 28

28 Finally we add an animated CODESYS Logo ( Waiting cube symbol from the Special controls tab) and arrange the elements nicely. Compile the project (Build->build) and perform a full download. Press F5 to enter RUN Mode Open a browser of your choice on your PC, smartphone or tablet, and enter the IP of your Raspberry Pi, followed by :8080/webvisu.htm i.e. We hope you have fun using PiXtend with CODESYS and are successful with your projects. We are always interested in your feedback. If you use PiXtend in one of your projects please mention PiXtend and our URL somewhere. 28 / 28