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About JiM_cz

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  • Country Australia
  1. Thanks guys, the PLF and PLS works. It's a bit more cumbersome but it should do the job.
  2. I need to write a small program for an old FX0S where I wanted to use a rising edge instruction but the GX Works2 doesn't offer me this option. After a quick google search it seems to me that this PLC doesn't have this instruction set. Is there any way around it? I still think that my project can't do without them...
  3. Main differences between FX1N and FX0S

    Thanks for your reply. Yes, one or two questions please. Can I connect the FX0S to the same HMIs as FX1N? I'm asking because I have both PLC units but the FX1N has insufficient amount of inputs whereas the FX0S has plenty of them that's why I'd like to replace it. I know, they're desperately out of date, both of them. But it's not a complicated application that's why I'd like to use second hand units for a cost saving.
  4. Could someone sum up  for me please the main differences between FX1N and FX0S PLC? Thanks
  5. "Unusual" use of a shift register

    Thanks. I think I got it. I tried to run that particular part in a simulator as you advise me to but my CX-programmer freezes every time. There is the hourglass icon hanging forever. Do I need to be connected to a physical PLC for the simulator to work?
  6. "Unusual" use of a shift register

    Yeah, you're probably right. That's how it works. But why? The help file describes the SFT function like this: "When the execution condition on the shift input changes from OFF to ON, all the data from St to E is shifted to the left by one bit (from the rightmost bit to the leftmost bit), and the ON/OFF status of the data input is placed in the rightmost bit." According to this, it should place the the status of the Always OFF (0) of the data input line to the the rightmost bit and never "1"
  7. Could someone please help me to understand how this particular SFT works please? (See the pic please). The first 3 parallel contacts ensure that 16.08 will be OFF (for 1 program scan) if there is a NG product that needs to be rejected. I'm confused with the part that follows. If 16.08 is OFF the H2.00 will be set to "1". H2.00 is also the rightmost bit of the shift register. However, at the same time the data input of the SFT is always off. My understanding was that when 16.01 is ON the SFT checks what is on its data input and puts it into its rightmost bit. In this case it should be always zero. But I must be wrong because I saw this code working and there were "1" as well (when the "not good" product needed to be rejected).
  8. Hello guys. I have just a basic question. What is actually  the difference between Run and Monitor mode of the PLC? I know that when I want to change the mode I get a message informing me that the mode will be changed and I should make sure it's safe. But what an "unsafe" situation might happen? I've changed the mode many times when I needed to do online changes or to force a bit and never had any problems with the running machinery. In the manual I've found many times a note that " When the operating mode is changed between PROGRAM or MONITOR mode and RUN mode" some memory areas will be cleared but again, I've never experienced any strange behavior of the machinery. Last thing. If I leave the PLC in Monitor mode permanently (instead of returning back to Run mode) is there any downside?
  9. Modbus RTU communication with Altivar VFD

    Thanks a lot for yr help guys. It's a bit clearer now. Btw, would Modbus with a CP1L processor look different? The provided material says the  Easy Modbus Master is only for CP1H... Can you also tell me what the Function Block might be used for?
  10. Modbus RTU communication with Altivar VFD

    It's CP1H PLC and it's a program in an existing machinery  that I'm trying to understand and modified. There is actually a small portion of FB but I'm not sure what it's doing and if it's related to the modbus frequency command but I don't think so. The code I posted is almost all that is there as far as the VFD communication is concerned. Then there are just zeros moved to 32305 and 32306. See the attached FB please.
  11. First of all, I'm very new with Modbus so please bear with me. I have a PLC program where you can set a VFD speed on HMI. Please see the attached pic. I understand that the values I'm moving into the registers mean: #1 slave no #6 I want to write #4 ??? (not sure what it is for) #2136 Where into the VFD I want to write (frequency) D6200 The set speed from the HMI But what I don't understand is where the addresses D32300 - D32304 come from? Where is it defined that the modbus will be using these particular ones? I went through both the Omron card (CP1W-C1F11) and the VFD documentation but I can't find anything about it.
  12. The card has more output points used. Does it mean I could expect some kind of "unpredictable" behavior? What exactly can happen?
  13. Hello Guys, sometimes it happens to me that when I'm monitoring PLC with my laptop through a USB cable the connection is cut with the red (or yellow?) flashing message at the bottom of the screen of the cx programmer. I have to unplug and plug in the usb (on laptop side) and press "work online" again. Sometimes it's more often, sometimes less. My USB cable is a new one and good quality (golden plated and shielding) and about 4.5 meters long. I remember I read somewhere in the manual that the max length should be 5m and that's why I'm confused why it's happening.
  14. Thanks a lot for your help guys, you've been very helpful.