Fernando Castro Posted October 8, 2022 Report Share Posted October 8, 2022 I know that it sounds weird, but I don't have any other explanation. first of all, let me tell you that I have one PLC (V700) on Wich on parameter seemed to be changing itself randomly. I don't think that its randomly because I was able to systemic repeat that problem (only on that PLC) I also have the same version of software installed on other PLCs (so far at least 10 running with no issues). Today I decided to tackle that problematic PLC so, I downloaded the most recent version of my software as follows: 1. First I did a Blank project download, with a burn upload project. 2. I went into info mode and did a plc Init to leave it entirely "virgin". 3. I downloaded the program using Unitronics download manager as I usually do with all my other PLCs. 4. I entered manually all the parameters required to run the machine this bit must be "SET" in this particular machine. 5. I did the machine's normal operation and then could spot exactly when that tricky bit was changed (after I loaded a recipe from the SD card and the confirmation of successfully read appeared on my HMI). 6. Checked the setting and the bit had a "RESET" value This is where that bit is being used, and can only be changed in 3 ways: 1. Is a setting, so naturally, it is linked to an HMI button. 2. When loading the default settings button (Buried 3 screens deep and needs to be manually triggered, also that defaults to "SET") 3. As you can see there is a RESET coil linked to that bit, and this is a feature Not a bug, let me explain: That setting is to select which type of sensor to use. There is an external control loop that is driven by a valve and a sensor, we have brands A, and B. valve A works with either sensor B or sensor A, but B valve can only work with sensor B, given this scenario, proper settings need to be entered on HMI to scale the readings of the sensor depending on if its A or B. so, if valve B is selected on HMI, sensor B is forced: This is the usage of MB122: Again, 1. Linked to an HMI button. 2. When loading the default settings button. So, I am confident that is not a problem with my logic. I also already look at all the MBs used on the function that loads files from the SD card (the trigger that happens to RESET MB129), thinking that maybe somehow, I am overriding that value with any vector operation and all MB'S used on that entire subroutine are in the 2000's range (I usually try to reserve my operands by functions to avoid those kinds of problems). Finally, I gave up and tried to replicate the problem on another PLC in my bench, downloaded the same software, imported operands from the faulty PLC then exported the operands to the bench PLC. The PLC works as intended. Doing the same steps MB129 is not being RESET after loading the recipe. I really don't want to say it, but it seems that it is the PLC that is not doing what was programmed to do. Quote Link to comment Share on other sites More sharing options...
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