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05-11-2005, 6:55 AM zaodao Joined on 05-11-2005 Posts 1 Opto22 in a semiconductor company i am a engineer in a Fab company,my company is sinomos,SinoMOS is dedicated to provide specialized and high-quality Wafer Manufactory Service; moreover, it has formed an alliance with specialized corporations from the design service, the packaging & testing, and the mask-making field, aiming to provide all-round service for the customers. we have many machines and tools,in our FAB,for good quality and speed ,we need excellent control system. when we use OPTO22 system,we meet many troubles and problem on software and hardware,we overcome these difficultity,we Install the Opto22 hardware following the Opto22 installation procedures. See the Opto22 ethernet controller help files for details on stablishing communication. we connect the controller and RS232 line,but no pictures on our controller computer,we cann't find the problem at first,although we change almost everythin,at last we change the Ip address of the computer,it appear to be seen ,all signal can show clearly on screen.we are very happy when we see it. one day I am having trouble programming. I can set up the flowchart. At this point I am having trouble making a counter work. I am using a digital input as a counter. I first clear the counter, then start the counter, and after a period of time I stop the counter and look at the counts, but I am not getting any counts. I watch the counter and see the XVAL is counting but the IVAL is not. nobody around can help me at that time,so i ask help on internet,and another kind man ask: The IVAL will not update unless otherwise you execute any read command related to the brain to which the input is connected. In a continuous running chart execute the command "Get I/O unit as Binary value" which moves the entire status of the brain to a Integer32 variable. You have to give the corresponding brain and a new Integer32 variable for this command If this command is executed continuously then your counter value will be continuously updated in the IVAL. You may seek my help on any further queries/clarifications To add further, you should use the command "GET Counter" or "Get and Clear Counter" command in some part of the continuous running chart to read digital input counter value. Hope this helps i do under his guide, and soon i reslove all problem.thanks for these people answer my question. my name:daixiwang adddress:No101 lushanxilu south area ningbo free trade zone ningbo zhejiang china city;ningbo province;zhejiang zip:315800 country:china telphone:0574-86825188-1417    Report

05-13-2005, 8:03 AM gmitchell Joined on 12-01-2003 Optomation Systems, Madrid, Spain Posts 144 Understanding XVAL and IVAL data Good to see that Opto22 experience in China is growing. Your problem is very typical when starting to work with Opto22 controllers and writing about it helps other people who find the same problem. The concept of IVAL (Internal Value) and XVAL (External Value) does not exist in many PLC’s and is more associated with distributed processing, especially in Opto22 systems. Its probably easier to think of I/O Units as separate devices that have no connection with Controllers. You can see the real-time value of any variable in the I/O Unit including I/O points (XVAL) through software tools such as ioControl, OptoControl, ioManager, but these are reading this data directly from the IO Unit. Opto22 controller based automation systems using ioProject or FactoryFloor allow the use of seperate controllers that can communicate with I/O Units. Because Opto22 I/O processors offer so much capability, it would be impossible to automatically transfer everything from the IO unit to the controller every scan. So as you have discovered, communication between controllers and I/O units is not automatic but under control of your application software, which needs to define what is transferred and when this must occur. This non fixed update is what makes Opto22 equipment so flexible and powerful. Every time the controller reads a value from an I/O Unit (XVAL), a copy of this value is internally saved in the controller and timestamped (IVAL). Similarly every time a controller writes a value to the I/O Unit, a copy of this value is saved in the controller and timestamped (IVAL). The IVAL and XVAL only will coincide at the time of reading or writing. Seeing the two values in the same window helps you to understand how often an I/O point is updating in the controller or if the application software is reading it at all! As you have discovered, counter data is updated automatically when reading the status of in input, or you can use a direct command to read its XVAL and transfer it into the controllers memory (IVAL). You can find out much more information in the user guides for your specific controller. The concept is also very important when working with PID control loops which also execute in the I/O Unit and interact with application software running in the controller. Now that you understand what is happening, it may be time to think a bit more about your application. 1. If a separate controller is being used, it is possible for the IO Unit to loose power and the controller continue running. Unless you have saved to flash in the IO Unit the status of the counter (ENABLE), the counter will not be enabled when power is restored to the IO Unit and will require a start counter command to be reissued from your program. 2. The XVAL counter value is not stored in the I/O unit, and will reset to 0 on start-up. If you have not updated and saved this value in the controller then the previous total will be lost. You will also need to consider some code to add the new total to the previous total. 3. If the counter is totalising something like a flowrate, then some extra software protection code may be needed. If your counter is not started, resets or disconnects from the controller, then the counter total is not valid. Checking that the total increases when a motor is running or flow valve open can provide a warning that something is wrong. Using the watchdog facility on outputs allows digital outputs to be switched off, if the controller stops communicating to the I/O unit. As you can see, to automate something is not so difficult, but to think of all of the possible failsafe modes and write software to protect the installation requires much more thought.    Report

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