Programming PLC via 3G DTU

chipwang
2011-03-31
2011-05-25
  • chipwang - 2011-03-31

    I tried downloading program to ifm CR0020 controller through 3G DTU and always had the same problem.

    At present CoDeSys downloads program to CR0020 PLC though RS232 cable or CAN bus. There is the requirement to program PLC through 3g network.

    There is a kind of product called 3g DTU on the market which helps to implements transparent communication for extending originally RS232 communication from local to long distance. By mean of this a PLC will connect to a DTU using 232 port and the DTU will be set up as TCP/IP client. There will be a TCP/IP server host on a PC , the server will simulate a COM port which CoDeSys gateway can access. The DTU will dial the server through 3G wireless network, once connected a communication channel will be established between PLC and the COM port.

    I tried two DTUs from two different suppliers with different baud-rates and the results are the same:

    The downloading process will always suspend on the final 10-50 bytes. I have to terminate Gateway.

    If this problem can't be solved, is there any other RS232 extension solution for CoDeSys?

    Will 3s go into COM port gateway and have a look at the code?

    Chip

     
  • chipwang - 2011-04-01

    By tracing the communication process , I found whenever Gateway receives "55 55 14 00 01 00" from PLC, the connection drops.

    Seems "55 55 14 00 01 00 " is a feedback from PLC to Gateway for a command sent by Gateway meaning something going wrong.

    Can somebody from 3S have a look at this ?

    Chip

     
  • spfeif - 2011-05-25

    I program cards over 3G. Here is the problem you might have with IFM. IFM CR0200 has no ram buffer (CR0032 does). So the PLC has no temporary storage place. Any lose of communication and you now have no program on the PLC. Big problem remotely. If you had ram buffer then if you lose communication no big deal start over because the main program has not been touched. You will also need to keep Pin 24 high all the time.

    here is what you should try. Go To Project->Options->Desktop-> and change the communication timeout to be much longer like 15-20sec for both.

     

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