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sending files using our dnc4U dnc communication software program

Once you have setup all your CNC parameters (see below) it is so easy to send DNC files to your CNC machine. If you have a file already open in the editor window, all you have to do is press the big Window icon - or press F3. Too many dnc software packages have, in our opinion, become too cluttered and difficult to use by non-computer literate personnel - we have tried to make our dnc software program as easy as possible to use with the minimum number of mouse clicks and non-essential icons.

There is no limit to the size of files you can send to your CNC, so you can drip-feed incredibly large files with no loss in speed.


main front screen of our dnc software program

Many free file transfer programs, such as Windows Terminal and many other DNC software packages just don't have enough "tweaks" to enable you to send successfully to your CNC. This is because many CNC machines are very temperamental about the way that data is transferred to it - it has to be just right or it won't work...

Our dnc4U software has many such tweaks for successful file transfer; we have included many essential parameters to help you get it right...

There are several different types of DNC send transfers with dnc4U.

Block Send. This is the most common type of transfer and is used when simply sending to your CNCs memory. It takes the NC code and sends it block by block.

Drip Feed. Sending in drip-feed mode creates a temporary image of your file. This has a double advantage. First it is so much faster to send data from your local hard drive, than it is to drag the data off a remote network drive. Second, should your file be located on a server, and the server crashes, transfer is not aborted because the file is no longer there. This is very important on long jobs taking several hours or overnight light outs jobs. The last thing you need is to walk into the jobshop in the morning to find the CNC hung there because the network has crashed.

Turbo Drip Feed. This mode is basically the same as above, but the file is not shown scrolling on screen, and all statuses are updating just once a minute. This makes for even faster transfer.

Executive Tape. This mode makes a perfect copy of the file and transfers it. Unlike drip-feed or block send where the file may be transformed from your NC code to code acceptable by your CNC - for eg end of block transformation or any send before or send after file CNC control codes, this mode is totally unchanged. This is useful for making backups of your CNCs executive tapes.

Drip In X Byte Chunks. This feature is very useful with some older CNC & PC combinations and drip-feeding. Fanucs for example will only issue an XOFF when there are less than 10 bytes in it's receive buffer. Responding to this fast enough can be a challenge for older PC's. If you drip at say 9 byte chunks, then there is much less chance of a buffer oveflow on the CNC.

Com Ports

dnc4U lets you set up as many as 64 CNC machines, with serial ports com1 to com128; more than adequate for the small, medium or large machine shop. This is a standard configuration, no messing about with upgrades like other DNC software packages that require more cash if you want to add more CNCs !

Because you can use a dedicated com port for each of your CNC machines you can easily use multi-port serial cards inside your computer thus eliminating those messy switch boxes! dnc4U fully supports these type of cards, as well as "normal" serial ports, USB devices and wireless/RS232/ethernet devices too.

We recommend Keyspan USB to RS232 converter cables, they are reliable, cheap and easily available in the US and elsewhere. They work with Vista straight out of the bubble pack! If you already have a USB to RS232 and it only works one way, the Keyspan will almost certainly work! In the UK we have bought them from here, elsewehere they are also readily available and they work!


com port settings in dnc4U software dnc communication software


Baudrates from 150 to 460800 are supported. Detect available com ports. Keep the com port alive so it's always online, or open and close between sends.

You can force the state of the CTS and/or DTR pins to go high as you open the com port - essential for many CNC that require a remote device to be online before it will open it own comms.

dnc4U uses the standard ISO/ASCII character set of nearly all modern CNC machines or EIA for some older controllers.

dnc4U supports XON/XOFF, RTS/CTS Haas Xmodem and Heidenhain Blockwise handshaking protocols with two different methodologies. You can use the CPU interrupt for the fastest response with a 16550 UART, or a polling method that looks for the state of the buffer or pins prior to sending, this has application if your computer cannot respond fast enough to XOFF characters, and so handshaking is ineffective.


Send Parameters

These are the tweaks that allow you to send your files to your CNC. What seems like an essentially simple matter of just sending a file to your CNC can in many cases turn you into a gibbering wreck and can be very frustrating, thats why we include these to make your life easier...


send tweaks for sending files to your CNC


You can send a series of characters to your CNC both before and after file transmission. This is because many CNC need specific characters to "tell" it that comms is about to start or finish. dnc4U lets you setup these characters as a series of ASCII values (since many of these characters cannot be types at the keyboard) Include delays in the character setups, essential to drip-feed to a Fadal.

dnc4U allows you to select different standard or custom End-of-Block characters as different CNC can require different sequences.

You can setup data packet delays of up to 500ms between each block and 25ms between each character that you send to the CNC. In many cases a block delay of just a few ms will cure many obsure communication problems.

You can choose to send your NC files block by block or as fixed-sized packets of data. Normally you would just send block by block, for upload and downloads to memory, but for example if you were drip-feeding, you can choose either drip or turbo-drip for the ultimate in transfer speed.

Many CNC require that a remote device is present before it will open its own comms, you can either wait for an XON before sending, or any character at all, in which case this process is automatic, or you can make a window pop-up that opens the com port and waits for you to setup the CNC and then press the button to start transfer.

dnc4U also supports old fashioned paper-tape machines. You can specify tape leaders/trailer etc. dnc4U comes with all the letters pre-set for man-readable leaders, and these are fully customisable to create your own versions of these letters if you require.


Sending Files

We have tried to make dnc4U really easy to use. We have tried to keep the number of click to a minumum. The easiest way to send a file is to just open up the file into the editor and press "Send Window" icon. Just one mouse click! Or you can select files from a normal file dialog box. You can select multiple files from the dialog box and send sequentially.

You can repeat count how many times you want to send any file. If you need to send and store executive tapes, you can, if your tool breaks some way into a file, you can start the DNC from exactly the point you specify in the file and restart from there.

dnc4U keeps a track of the last files sent, so you can easily just resend if you need to start again. You can find a file quickly using the search and send. You can send in binary rather than text mode.


Example Setting

To get you started we have included a list of popular CNC machines and their settings. These are starting points, since many of the simple parameters such as baudrate may have been altered, but will nontheless get you going. You should note that if your CNC is not in the list, its not that we can't communicate with it, its just that we may not have included it - it will almost certainly work, but it may need a bit more trial and error on your part


example settings for many popular CNC machines are included with our dnc software proram



Each CNC can, if you want to, have its own different send and receive folders so that you can keep files that are proven separate from files that have been received back from your CNC.

In addition you can set up to eight different file extensions for each folder. This is extremely useful if you want to differentiate between customers without having to setup different folders for each one.



If you use either an ethernet to Rs232 or a wireless device, then dnc4U will send and receive files direct to these devices by creating a direct TCP/IP socket, there is no need to use virtual or port re-director software.

If however you should choose to use your wireless hardware vendors virtual ports, you can. These virtual com port are seen by dnc4U just like any other com port on your computer. dnc4U does not "know" any difference between these virtual ports and the com ports that may be around the back of your computer and they behave exactly the same. As a visual aid dnc4U has a wireless monitor that shows graphically your wireless devices and whether they are online or not. You can also PING these devices to test they are online.




If your CNC supports ftp transfers then your data transfer will be so much faster, in the gigabits rather than kilobits of Rs232



Queue Files

If you need to be able to setup a list of files, either for your own use or for someone else, the DNC queue lets you save away a list of files that can be picked off individually or queued for DNC. This is great because it saves the operator either wondering what files to send and having to pick them off laboriously every time. You can even set it up so that your most used files are always at your fingertips. Each CNC can have its own schedule.

If several files are selected then they are sent one after another to your CNC machine.



Historical Log File

dnc4U keeps a track of all files sent and received. Not only does it keep this track, but all you have to do is "Repeat Action" and the file will be sent to exactly the same cnc again.


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