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IndustryArena Forum > Machine Controllers Software and Solutions > Fanuc > DNC Server on 18i - Hardware or Software Handshaking?
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  1. #1
    Join Date
    Feb 2009
    Posts
    23

    DNC Server on 18i - Hardware or Software Handshaking?

    Hi All, new to the forum, new engineer, looking forward to being involved in the community.

    My task is to hook up two Fanuc 18i Model A and Model B controllers to a DNC server. We are using a USB to Serial adapter.

    I am a little confused as to the difference between Hardware and Software handshaking and which one we will be having to use with this new DNC server. As I understand it, Software Handshaking (which the 18i is) must use Xon/Xoff.

    I have the parameter manual in front of me and have detailed the bits that need to be changed.

    My question is, is this setup possible with the USB to Serial adapter?

  2. #2
    Join Date
    Apr 2007
    Posts
    126
    Quote Originally Posted by RC-CNC View Post
    Hi All, new to the forum, new engineer, looking forward to being involved in the community.

    My task is to hook up two Fanuc 18i Model A and Model B controllers to a DNC server. We are using a USB to Serial adapter.

    I am a little confused as to the difference between Hardware and Software handshaking and which one we will be having to use with this new DNC server. As I understand it, Software Handshaking (which the 18i is) must use Xon/Xoff.

    I have the parameter manual in front of me and have detailed the bits that need to be changed.

    My question is, is this setup possible with the USB to Serial adapter?
    As I remember The 18i is fairly common control and can be connected either way. look in the design drawing section for communication and double check the pin assignments for serial connection. you can get the adapter to go either way!

    Does the control have a disk drive installed! If not it's probably serial only!

    Hope I helped


    Jim

  3. #3
    Join Date
    Feb 2009
    Posts
    23
    Okay I am just plunging into it. I am getting a '071 BP/S alarm' when I try to output a program, what could this mean?

    EDIT: Solution: On page 561 of the Operation Manual (B-62444E/03) it says that 71 is 'An invalid file number or program number was entered. (Specified program number is not found)'

    The problem is that I did not enter in a program number to output when attempting to send from CNC to PC.

  4. #4
    Join Date
    Jun 2008
    Posts
    1511
    It’s been awhile since I had to do this with the 18 series control. When you are trying to send a program out of the CNC when you press “program”, over arrow until you see the “punch” softkey once you press the “punch key I believe the options are “all” or “this”. If you press “all” it will punch out all programs in your directory other than the ones that are locked which are usually the 8000 and 9000 programs. If you press “this” it will send out only the program that is currently called up and displayed on the screen.

    I don’t remember if there is another key you can press like “prog. #” that you can then specify a certain program that you want to send out by typing the program O1234.

    You have to specify a program that exists in the control that you want to send out.

    If you need to backup your 8000 and 9000 programs you must unlock them via parameter setting.
    #3202 bit 0 locks your 8000 programs
    #3202 bit 4 locks your 9000 programs
    Bits run right to left (76543210)

    Stevo

  5. #5
    Join Date
    Mar 2003
    Posts
    2932
    If there's a program in the memory, you should be able to punch that out in EDIT mode, PROG function, >, PUNCH, EXEC.

  6. #6
    Join Date
    Sep 2005
    Posts
    767
    When the 18i is sending data, it only handshakes using RTS/CTS. Your PC can stop the Fanuc from sending by driving CTS (pin 5 on the Fanuc) low. If pin 5 is high, the Fanuc can send. Some people jumper out pins 4 and 5, but that would let the Fanuc send data even if the PC wasn't ready.

    When the Fanuc is receiving data, it only acknowleges Xon/Xoff. The RTS/CTS signals won't do anything, but CTS must again be held high, otherwise the Fanuc can't send the Xon/Xoff characters.

    USB-to-Serial adapters pose some problems because they usually have larger buffers. When the PC is sending and the Fanuc issues an Xoff, the PC must stop sending within 10 characters or else a "Buffer overflow" alarm will happen. Many DNC systems can't react to Xoff fast enough, and you may have to turn down or disable the FIFO buffer in the serial port. Right-click on "My computer", select "Manage", then "Device Manager", then click the "+" next to "Ports (COM and LPT)". Then, right-click on your COM port, select "Properties", then "Port Settings", then "Advanced". Turn the "Transmit buffer" to it's lowest setting, then click OK many times to exit all menus. That should help eliminate the "Buffer overflow" alarms with most DNC software.

    We recommend that you set your DNC software to send ASCII even parity, with Xon/Xoff handshaking, 7 data bits, with either 1 or 2 stop bits (stop-bits must match setting in Fanuc parameter 101). Also, be sure to set parameter 102 to "0" so that the Fanuc sends Xon/Xoff.

    Here's a recommended cable diagram:

    Fanuc 25-pin male -------------- PC 9-pin female
    pin 1 -------------- cable shield
    pin 2 ----------------------------------- pin 2 (data Fanuc to PC)
    pin 3 ----------------------------------- pin 3 (data PC to Fanuc)
    pin 5 ----------------------------------- pin 7 (CTS on Fanuc to RTS on PC)
    pin 7 ----------------------------------- pin 5 (signal ground)
    pin 6 and pin 8 ------------------------- pin 4 (DTR on PC holds DR and CD high)

    The CD (pin 8) and DR (pin 6) signals on the Fanuc must be held high also to avoid alarms. Some people jumper 6-8-20 on the CNC side, and this works MOST of the time. Some newer Fanuc controls will still throw DR alarms with pins 6-8-20 jumpered however, so we now recommend that you tie pins 6 and 8 to DTR (pin 4) on the PC side.

  7. #7
    Join Date
    Feb 2009
    Posts
    23
    I jumpered 6-8-20 together and no longer received 86 alarms. I was also able to send and receive successfully.

    What is the significance between 1 or 2 stop bits?

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