Mendon Systems

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About Mendon Systems

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  • Birthday 08/16/43

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  • Location Mendon, NY
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  1. Control panel testing

    OK ... I see what you are after. Whether that will work or not depends on how much inrush current those VFD's draw. I would not be at all surprised if you wiped out some fuses. Is there a way that you could power up the VFD's one at a time?
  2. Control panel testing

    The way you described it you would be backfeeding the 1.5kva transformer through the secondary windings. Don't you have separate protection to isolate the devices on the 120 volt secondary?
  3. Omron CJ1M -cpu12 - ETN - cennection

    The default IP address for the ETN is 192.168.250.node# (node number set on rotary switch). There is a small chance it might still be set to that IP address. If it is you must use a PC set to the same subnet to establish communication with CX programmer.
  4. CP1E TXD problems

    Sounds like your cable is missing one of the handshake jumpers. 4-5 should be jumpered at the PLC end and 4-6 & 7-8 on the PC end.
  5. Real world simulator

    If you really need that capability then connect a second PLC and write a simulation program strictly for testing. I have done that before on the rare occasion where I needed active simulation.
  6. One thing that will help is to break the project into separate logical tasks and create a program section for each task. That will allow you to arrange the program sections in a logical order even if you don't write them that way.
  7. Internal Counter Holding

    You still haven't told us which PLC you have, but assuming that it is reasonably current you should be able to use the ++(590) and --(592) instructions to manipulate the value in a DM or H register. Those register values will be maintained during a power cycle.
  8. Immediate Refresh

    One thing to keep in mind when using immediate refresh: The I/O point referenced by the immediate refresh can change state in the middle of a program scan which could mean that any rungs which reference the I/O point before the refresh get different results than those after the refresh. In most cases this won't make any difference, but there is a possibility that it could cause weird results in the logic which are extremely difficult to debug.
  9. Control Transformers in a Control Panel

    If it was powered by 208Y then no problem, but 230 comes in various flavors depending on where you are located. Some 230 sources have a neutral reference that provides 115 volts and others don't. There is also the infamous "wild leg" 230 that has one phase which is at 284 volts to the neutral. It is a whole lot safer to use a 230/120 control transformer.
  10. Program lost after power cycle

    Also check the DIP switch settings on your CPU. The settings of switch 2 (and 7 depending on the CPU type) can cause the CPU to try to load from a memory card on power up. Start with both switches OFF and configure from there.
  11. TIM instruction is not working

    I suspect that something in your logic is resetting the timer as soon it reaches zero.
  12. P_WR, P_CIO

    Those two, along with several others refer to words A450 through A473. They are used as pointers by OMRON FB Library function blocks. The programming manual says "Do not change the content of these words".
  13. Count how many words are being used

    It seems like you should be able to use the SRCH(181) instruction to do that. It will output the number of matches found to DR0. It is listed under Data Table Processing instructions in the W474 manual. I suggest that you search for words containing zero. The SRCH instruction will give you a count of them in DRO. You can then subtract DRO from the total number of words to get the number of non-zero words. Nonzero word search.cxp
  14. Count how many words are being used

    What do you mean by "used"?? Do you want to count words which contain a non-zero value??
  15. Cyclic Tasks

    The SFCON and SFCOFF instructions in rungs 7 & 8 of task 0 control the operation of cyclic task 1.