Drip Feeding - Page 2


View Poll Results: Do you know what "Drip Feeding" is?

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  • Yes, I use it all the time!

    71 56.80%
  • No, I haven't a clue!

    54 43.20%
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Thread: Drip Feeding

  1. #21
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    I’ve been a software developer since the mid 70’s
    In the early 80’s I wrote my first Communications software for the Machine tool Industry.
    The Definition of DNC means both of what has been discussed in this topic.

    First it Means “Distributed Numerical Control” this is the process of Transferring a Program into the Controls Memory.

    Second it Means “Direct Numerical Control” in it’s earliest form, this meant that the CNC control Executed the commands as they were received through the RS232 port.

    The Earliest form of Direct Numerical Control was Punched Paper Tape.
    In effect, the Tape could be as long as necessary. The program was executed directly by reading in a block of code from the tape, stop the tape, execute the block, read the next block, execute it, and so on….

    The Limitation was how much tape you could fit on a Spool.

    Very early DNC systems that used a PC also used a BTR (Behind The Reader) device to replace the Punched Paper Tape Reader. Instead of the Control executing the program from a punched Tape, the program was executed from the BTR device which was being fed instructions from the RS232.

    Now BTR devices and Punched Tape are rarely seen or used.


    There is a use of “Direct Numerical Control” that should more accurately be called “Buffered Input”.
    Many controls will now input Data from the RS232 port into a Memory Buffer, the CNC then Executes the Codes from this memory Buffer, as the Buffer is emptied, more data is requested to keep the buffer full. This type of buffer is also known as FIFO or First In First Out.

    Some controls use very large memory Buffers, while others use a very limited buffer size.

    So basically the Definition of DNC depends on the context of how you plan to use it.




  2. #22
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    070103-2208 EST USA

    vpcnc:

    You have provided some very clear definitions.

    Big problem is that most persons that use the term DNC provide very little "context" information to clarify what they are talking about. I suspect this results from a lack of knowledge of the possible meanings of DNC, and that clairification is needed.

    I have tended away from using the term DNC by itself. I like the term "drip feed" because it quite clearly identfies the subject. When I use "drip feed" there is usually enough "context" that indicates I am talking about data transfer, and not lubrication or coolant.

    .



  3. #23
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    Who in year 2007 use drip-feeding !!! Ethernet rules....

    M30 <-- rewind tape !!



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    070217-1721 EST USA

    LeonH:

    Drip feeding has nothing to do with the communication path.

    Drip feeding needs to be used if the program to be run is larger than the available CNC program storage area in the CNC machine.

    If the CNC has a hard disk and the CNC program is too large for the available RAM in the CNC, then you will effectively drip feed from disk to RAM.

    .



  5. #25
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    Default Drip Feed What Year

    Most Pc Retrofit Machines Dont Need Drip Feed,mine Is Mach3 Dell
    1000 512 Ram Ethernet To Amd64 Cad Cam Just Pull The Whole Program Over In Adout A Minute No Buffering In,drip Feed Is Normally Hardware Based Cnc Older Like Dynapath, Etc With Almost
    No Ram



  6. #26
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    Default drip feed vs/dnc

    99 % of shops use drip feed. It allows control of the actual machine on the operator panels. It's the safest way of running long programs if they wont fit in memory.
    Think DNC as your operator controls are in a different location. Machining explosives for instance, you really don't want to be in the same room, but you need to be able to control the machine still.



  7. #27
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    Question touch probe

    New on here, having problems using touch probe cycles on old hiedenhain 426, will go in and find bores shafts etc etc but coming up with message incorrect number for fn17/fn18 which are syswrite and sysread parameters. is the control set up or not,if not how to set it would be good

    ta
    mick



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