JiM_cz

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About JiM_cz

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  • Country Australia
  1. 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?
  2. 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?
  3. 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.
  4. 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.
  5. The card has more output points used. Does it mean I could expect some kind of "unpredictable" behavior? What exactly can happen?
  6. 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.
  7. Thanks a lot for your help guys, you've been very helpful.
  8. What worries me is that the manual from the D/A card stresses "Never connect a voltage or current source to an analog output channel." I don't want to blow the card..
  9. Hello Guys, I have an Allen Bradley 1769-OF4VI Isolated Analog Output card 0-10V and I'd like to use it to control speed of an Omron VFD. The VFD has the ordinary frequency analog input where you normally put a potentiometer. Can I connect the +V and -V of the output card to the analog input of the VFD? Please see the attached pics. I'm thinkng about terminals FV and SC.. pic.docx pic.pdf
  10. Thanks a lot for your response. I didn't realize that the diagram is actually showing when the Bs are reflected on the outputs and not it the program itself. Could you just confirm for me please (or correct) that the working bits work the same way as the physical ones? I.e. The B1 would behave the same way for Y:101.01 as for W0.00?
  11. I'm sorry guys to take space here with such a basic problem but I'm a bit confused by the I/O Instruction Timing table that I found in the manual (see the pic please). Basically, I always thought that the status of the individual bits will be reflected in the program just after the I/O refresh, that is the PLC will check the physical inputs, copy them into the image memory and use them (update) in the following scan. But by looking at the table, it's not apparently true. I can see that in case of B1, after the I/O refresh there is a full scan where the B1 is still OFF and it come ON only the scan +1. Only when I use the (!)  then in works the way I thought it should work even with a simple contact. Can someone explain to please why there is the full scan gap?    
  12. GOT 1155 won't communicate through USB port

    I've just tested another screen of the same type and the USB communication works. It seems that the 1st screen has the USB port faulty. Does anybody know if I can swap the particular part of the HMI that takes care of USB? BTW, I've heard I can read and write to the PLC connected to the screen with 422 through the USB port connected to the laptop. Can I do the same if the laptop is connected to the screen through 232 port and not with USB?
  13. GOT 1155 won't communicate through USB port

    Might it be because my Windows are 64 bit?
  14. GOT 1155 won't communicate through USB port

    I've tried to install the stuff from Easysocket folder but windows has decided that "the best driver is already installed".. :( What should actually be in the device manager instead of "unknown device" when the suitable driver is found?