Serial Port Issues

[Egar Twins]

Gentlemen,
I am working with two Bavelloni CNC stone working machines equipped with NUM controllers. All are connected directly to a PC via Null modem serial cables RS232, one at 200' and the other at 50'. We recently upgraded our engineering room to an XP PC up from 2000 Pro and now we are having communication problems. I have toyed with and even turned off the FIFO buffer as per the manufacturers suggestions to know avail. Initially, a program would attempt to send, and stop, displaying a message on the NC " program exists do you wish to overwrite" to which I would key yes and then the program would continue sending. No matter, the end result would still be a serial line error being displayed or a program 0 ( not the number I sent) being displayed with nothing in it but a jarbled mess. After toying with the FIFO ( and then turinging it off) I can now get the machine(s) to recieve the programs in one continuous shot however, the result is still the same(serial line error or jumbled mess in "0")....If I reconnect the machines to the older computer ( switching nothing but the cables between PC's) the programs sends fine with no errors. All settings in the transfer software on the two machines is identical. The only two differences between the two PC's is that the older one has two serial ports that are wired directly to the motherboard ( OEM) and has windows 2000. The new one possess PCI card serial ports (both on the same card) and runs XP.....PLEASE HELP....the older machine is dying and I need to keep my engineering room rolling at full steam!!!!!!!!!

your friend in technology,
Jimbo

[debco99]

I use XP all the time on Num controls as we are an OEM with Num.
What control?? 1040 series? and are you using com1 or Ser 1?
I would slow the baud down to 4800 and try it.

Otherwise you may have to dump the computer you are using.

Regards

[Egar Twins]

Debco....it is a 1040 on both machines. We have tried slowing to 4800 with no luck....Both machines are setup on the serial line.... I am going to try com1 at the NC today however I jsut dont understand why it works fine on the old computer and there are errors on the new?

[gar]

070601-0653 EST USA

Egar:

I know nothing about your CNC, but I have some questions.

1. Is there any difference if the new computer is connected thru the short cable to the short cable CNC?
2. Are you using software handshake, meaning XON/XOFF?
3. Can you take the new computer to the machine, and run a short RS232 cable to the CNC?
If this is possible, then connect the safety ground pin of your 3 prong AC plug with a #16 wire to the metallic chassis of the CNC and see if this makes any difference.

Do run with the FIFO disabled.

In general I suggest 7 data bits, even parity, and 1 stop bit. Both ends must be exactly the same except for a few strange machines where apparently the parity is not check in the UART.

.

[Egar Twins]

Gar,
Thank you for your attentive response!!!!
To answer your questions:
1. There is a difference in result between the long and short cables on the new computer. On the short cable I recieve an actual " Serial Line Error Block N0" with no info at all being sent. On the long cable I do not recieve any error messages, however I get the " Program exists do you wish to overwrite?" message which I must clear a few times before for the program coming from the PC to be completely sent. However, the only thing I get on the long cable is a jumbled mess.
2. The protocol in the software ithat is working on the old computer is RTS, I do not believe there is any software hand shake being used
3. I will take the new PC down to the NC and see if a super short cable makes a difference on Monday as I did not get your post until late. Is it possile we are having a grounding issue? I am not sure how the cables are grounded they were purchased on line before I began with this company.

Thank you so much in advance for your help!
Jimbo

[gar]

070601-1831 EST USA

Egar:

That you are not using software handshake, but are using hardware, RTS/CTS, means you must run at least 5 wires between the computer and the CNC. You may also need to jumper pins 6, 8, and 20 together at the CNC 25 pin connector. For reference: on HAAS controls 6, 8, and 20 are do not care, but on Fanuc are required and maybe under some circumstances have to also handshake with the computer.

See my web site www.beta-a2.com for some wiring information on the E232 Photo page. This may or may not apply in your particular case. The schematic is not for computer to CNC, but it and the description give you broad background information.

Do study the information on grounding and noise.

If you are using hardware handshake at your CNC, then you must use hardware handshake at the computer. And this means at least 5 wires. But I believe you have other problems, like noise, and I think the short cable test and solid ground at the CNC chassis may help prove this. The common wire, pin 7 in the 25 pin connector, pin 5 in a 9 pin connector, is inadequate to reduce a ground voltage difference when there is an external ground difference with high current capability.

Your answer 1 is confusing. But I believe you are saying with the new computer you can not get any transfer with the long cable, but with the short cable you get error messages and after many tries may get the program to load.

Relative to your answer 3. By NEC (National Electrical Code) code your CNC should get a safety ground connection from the chassis of the CNC (meaning conductive, metallic, material on on the CNC) back to the service entrance from where power is supplied. This conductor must be as large as a power conducting wire. Similar requirement from the wall outlet where your computer is connected back to its main power panel. These safety ground wires are a much lower impedance than the signal common wire in your RS232 cable.

If when the computer is near the CNC you still have problems call me. The phone number is on the web site. I am in the eastern time zone.

.

[Egar Twins]

Gar,
Thanks so much for the input...answer 1: short cable(50') gives serial line error. Long cable....I recieve no error but the program gets stuck and comes through in pieces...when i open the program on the NC ( long cable) it is nothing but garbage.
thanks Jimbo!



ps do...you know of any reason why the old PC still sends ok...but the new one does not?

[gar]

070601-1936 EST USA

Egar:

If the RS232 board has less output swing or a defective output driver, then this might expalin the problem.

On the 9 pin computer connector pin 3 is the output and at rest, a logic 1, no data being sent should be present. Older RS232 drivers have a voltage of about -9 to -12 V relative to pin 5, or the computer chassis. Newer drivers may be nearer -5 V which will reduce the noise margin. Also a driver might not swing equally between equal +/- voltages.

.

[Eurisko]

Egar,

Try a different PCI serial card.

I agree with Gar, the problems you are having can be caused by low voltage levels on the serial lines. The fact that you are experiencing different problems with different lengths of cable is a dead giveaway.

[Egar Twins]

gentlemen,
thank you for the as always prompt responses.
Would it be accurate to say that because i have a twin port card the voltages is being split between the two ports thus rendering rendering each individual transmission in adequate because of the split voltage. Would single cards, each on its on pci slot drawing its own voltage remedy this?
It make sense....! Good deal
thank you all for your help
Jiimbo
i will try two single cards monday

[gar]

070601-2139 EST USA

Egar:

Twin portness should have nothing to do with your problem.

Two, 10 or whatever number of ports does not split voltage. The voltage is set by the circuit design.

.

[bborb]

The PCI bus does not support -12 volts as the older ISA bus did. If you have an available ISA slot in your XP machine, get an ISA card with a serial port. Don't buy another PCI card.
I'd put a new powersupply in your 2000 computer and clone the harddrive to a new harddrive, replace the CPU fan (and any others), then use the 2000 machine for another 5-7 years.