Joe Tauser

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Joe Tauser last won the day on May 22

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About Joe Tauser

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  1. First off, use COM Port 2 for Modbus unless you have no other choice. Port 1 is used for programming and OS updates - the PLC will stomp on your communication code if you need to log in while the program is running. You want to use the SCAN_EX block in new applications. The SCAN blocks are for legacy support. Be sure to read the Help on "Slave Address Tables" to see how Unitronics maps Modbus addresses. I modified your code a bit to show good programming practices. You had several logical statements in one net in several locations, which is generally a no-no. Look at what I've done and you'll understand. Additional nets cost nothing, but having too much going on in one network can cause unexpected behavior because of the compiler. I found this on the web for the Pi side: Joe T. modbus car spray1 JT.vlp
  2. Thank you for the contribution! Joe T.
  3. You can do this, but you need a DC MOSFET SSR. A regular one won't turn off, as the triacs in it are waiting for the supply to cross zero volts. Which won't happen. Your motor will draw 21 amps, so get a 40 amp unit. You'll need to mount it on a heatsink. Joe T.
  4. Does this problem bring back memories! Windows NT 4.0, no less. You have a memory leak. Unitronics programs were originally written in VB. I don't know if all them were ported to .NET; that is a question for the Creators. Start with this suggestion: You'll have to determine if DataExport is growing larger as it runs, like The Blob from the 1958 classic movie. Let us know what you find. Joe T.
  5. I'd slow your timer down to 10 sec or more so you can see what's going on. I also always include a Copy Buffer block and select another MI area to look at the last buffer value. A little-know secret in Visilogic is the Memory tab at the bottom. Enter the beginning register of your copied buffer, set the length, Size 8 bit, and Format ASCII. You'll be able to see your buffer data in readable form. Troubleshoot your code from there. Joe T.
  6. A 1X is an input in Modbus land. If you're working with MBs you have to stay with 0x addresses. List some the addresses you're trying to write. Joe T.
  7. The string format in the Scan function block only works if the string is guaranteed to have the same format every time. Yours does not, so you need a different method. The proper way to do this is to use one massive stream variable and then strip off what you don't need using the string function blocks. If you'll post your .vlp code I'll make some modifications to get you started and put it up. Joe T.
  8. Hello Joe

    I need a sample for Unitronics Sm43 for High Speed counter for measuring proximity sensor impuls ?


    Best regards

    1. Joe Tauser

      Joe Tauser

      Can you be more specific with what you are trying to do?

      Joe T.

  9. Going to Info Mode automatically indicates that your touch screen has shorted out. Joe T.
  10. Reviewing it today I realize that what I wrote won't work; it was late when I put it together. As I like to say, my code never works right the first time. Take a look at this Joe T.
  11. Calorie free. Enjoy! Joe T.
  12. Both Aus and hotwires are correct in suggesting deadband control. Your output is going to chatter incessantly with one compare block, which is basically trying to hold 1 PSI. Here's some simple hysteresis logic for a Jazz: Feel free to critique my logic. I didn't have a Jazz handy to test it on. Joe T.
  13. The PLC clock is usually accurate to a minute a month. It should not drift as much as you are noticing. You did not state your frame of reference for observing time. Is it on the PLC screen, or are you communicating with the PLC? Serial or Ethernet? At the end of the day, the PLC clock can be counted on to 0.01 second. If you need better than this you need another device. Post your code so we can see what you're trying to do with synchronization. Joe T.
  14. Look at the existing Modbus examples to see how the function blocks go together. It looks like you can talk to the drive using Modbus rtu via RS 485. Look at this document starting on page C-2 - Have you done any type of Modbus before? It's not the simplest thing to do in Unitronics if you don't have a firm grasp on the Modbus protocol . You may want to look at my post at the bottom of this thread: Joe T.
  15. Thanks for the update! It sounds like you've learned some of the secrets of Modbus troubleshooting. You can't beat an external program and a 485 converter to find the gremlins. Joe T.