[bob@apc]

hi all,
we networked 3 of our cnc machines and we are having trouble recieveing data from one machine to our pc. we can upload programs from machine to our pc but we cant download programs back to the machine. the 2 machines that do work are mills , 1 with a meldas control, the other with a fanuc o-m control. the trouble is with our lathe with a fanuc 21i-T control. we swapped cables with a machine which does work both ways, that has about the same length of cable and we can transfer programs both ways so thats not the issue. cable length is about 100 feet. thing is if we use the same laptop with a cable of about 3 and another cable of about 20 feet we dont have these issues.
thanks for any help
bob

[dcoupar]

The 21i-T should use the same cable wiring as the 0-M. What happens when you try to send to the machine? Does LSK blink? Do you get alarms? Have you tried sending a program to the PC then sending the same program back to the CNC?

[bob@apc]

hi dcoupar
everything at the machine looks normal..lsk is blinking like it does when it waits for the pc to send. we get no alarms. we tried sending and recieving the same program, so thats not the issue either. i called fanuc tech support and even hes scratching his head. odd thing still is that we can send and recieve with same pc if we use our short cables, not our networked cables and switch box. we know our switchbox is good..so more and more its looking like cabling,,but are open for thoughts., cabling isnt shielded but the computer guys didnt think we needed that type. cables are about 100 feet in length, not following electrical runs, not really close to lights so we think we have those areas covered. fact still is though we are having trouble with our long cables. does anyone else know if a certain color/pin configuration is better for tranferring data within the cable or is it just wires and as long as the pin configuration is as layed out in the maunual that it should be fine regardless of wire colors?

[fanuservicetech]

Have you consider using flash memory card to transfer programs. All you need is Flash memory card PCMCIA type, set I/O = 4 on setting page of the control. Operation for read/write program is the same as using RS232.

[dcoupar]

I highly recommend shielded cables. If you can send and receive to/from this control with the same PC using shorter cables, then the problem has to be something in the cables/switch box. Have you tried the same cable without the switch box? Have you tried putting a simple RS-232 tester on the end of the cable and watching to see if the LED's show data flowing when you send to the machine using the long cable?

Re: the PCMCIA memory card. I personally don't recommend that if you can get the RS-232 working, as I know of at least 2 customers who have damaged the connector when inserting the card, and had to call Fanuc in to repair it. Luckily, in both cases the controls were still under warranty. Don't know what the $ would have been if they weren't.

[Dan Fritz]

The Fanuc 21 will blink "LSK" until it receives an end-of-block character. In ISO (ASCII) tape code, the EOB character is a line-feed, and in EIA (RS244B) code, it's an EIA End-of-block character, or Hex 80. Once LSK goes off, the control begins to read data.

The fact that LSK does not go off indicates that the control is not receiving a valid EOB character, so one of these three things must be happening:

1) The DNC software you're using isn't sending any data
2) The DNC software is sending data, but the data isn't getting to the CNC
3) The DNC software is sending data, but the data is not recognized by the CNC because of baudrate, parity, or tape code mis-matches.

If you're using EXACTLY the same DNC software with the same settings when you use your "short cables", then we can rule out (3) above.

If your DNC software is sending the file when you try to read it on the CNC, then we can also rule out (1) above. If it's not sending the file, maybe the DNC software isn't receiving the "DC1" or "Xon" control code when you press READ/EXECUTE on the CNC.

You could have a bad cable between the CNC and your networked switchbox (is it an Ethernet serial device?)

Can you send data the other way (CNC to PC) through the networked switchbox and the long cable? If you can, then there's no excuse for the DNC software not receiving the Xon from the CNC.

Hope this helps a little.

[fanuservicetech]

I highly recommend shielded cables. If you can send and receive to/from this control with the same PC using shorter cables, then the problem has to be something in the cables/switch box. Have you tried the same cable without the switch box? Have you tried putting a simple RS-232 tester on the end of the cable and watching to see if the LED's show data flowing when you send to the machine using the long cable?

Re: the PCMCIA memory card. I personally don't recommend that if you can get the RS-232 working, as I know of at least 2 customers who have damaged the connector when inserting the card, and had to call Fanuc in to repair it. Luckily, in both cases the controls were still under warranty. Don't know what the $ would have been if they weren't.

OK. If you damage the connector because you insert the card wrong, all you need to do is replace the card reader slot which cost about $70-$80. If you damage the RS232 port because of electrical/power surge, you will have to replace the main CPU board on 21iT control (which last checked cost over $1800). Personally, I recommend using the PCMCIA card slot to transfe programs especially since you are having so much trouble setting up the RS232. By the way, PCMCIA card reader slot is keyed and the card can go in only one way. Yes it is possible to damage it by forcing the card in when it clearly does not fit and it is not fool proof. If someone managed to damage the card reader twice during the warranty period (usually 2 years), its a first I know of. And why did Fanuc cover it under warranty twice? Because it cost $80 a piece. Try damaging your RS232 port twice and you will be arguing with them about warranty coverage.

[dcoupar]

I'm guessing that Fanuc covered it under warranty twice because it was 2 different customers.

[bob@apc]

thanks for all the suggestions. what it came down to was that our wiring between the switch boxes was not correct. when we stepped back and realized that the switch boxes are nothing more than pass throughs, the cable pinning solution between the boxes was fairly simple. before leaving work we were able to communicate to and from our machines