Can any CNC/computer people help?

Hello everyone,
I hope some of you guys could help me out? I've got a CNC milling
machine hooked up to an old (Pentium 166) PC running Win98 via the
9-pin serial port (com1). It works fine, but no matter what settings
I change, I can't get it to work on com2, and more importantly, when I
try to get it to run on a brand new PC (which it will have to do, as
we want to get rid of the old one) it doen't work properly.
On the new PC, it only seems to want to RECEIVE data from the
machine, but when I try to TRANSMIT data to the machine, it does
When I tried cables with the Rx and Tx swapped around, it didn't
even want to receive data. I've tried it on two other new PC's runing
XP with the same results. There are no conflicts and no serial
mice/modems etc.
Any help you guys can offer would be such a great help!
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If the connectors are DB-9s see if (7,8) are jumpered together and (1,4,6) are jumpered together, and that 5 goes to to ground on both.
The pin numbers for DB-25s would be a bit different.
Maybe a dumb suggestion, but the first thing I'd try. Do you have a logic probe or 'scope to look at pin 2 & 3 (Txd and Rxd)?
Best regards, Spehro Pefhany
Reply to
Spehro Pefhany
COM2 probably has a 25 pin connector rather than the 9 pin on it so you will want a 25 to 9 pin converter cable (they're about 6" long with the right connectors on each end - there are two sexes of these so get the right one) to work right. I'll also note that some software only works with one port and even changing the enabled ports won't help. You may also be having problems with the OS if you have XP running as it requires some instructions allowing it to allow for external communications via serial and parallel ports. If you have the hardware working on one computer with a particular cable, that same cable should work with another computer without problems although you might have speed problems with the new computer, some software weinies just don't seem to understand that internal loops are a poor way to control timing issues.
-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!
Reply to
Bob May
Have you compared Baud rates, parity settings, handshaking, etc?
On the original is Com2 enabled in the BIOS?
Reply to
Yup, you were right! I swapped the old HDD (win98) into the new machine, and it all works well. Looks like I'll have to downgrade this machine permanently to 98 for it to work, but thats no big deal really. I tried running the software in '98 emulation' mode in XP, but it still didn't work.
Thanks for all your help guys, at least I know what the problem is now!
Reply to
If you're using a dedicated computer, there's a lot you can rip out of Win98 that is just not relevant to the job, and that will speed things up a lot. You can use outdated machines from the office instead of buying new, and get new computer performance from them. From the discussions I hear.
To dump Internet Explorer from Win9X (improves virus resistance):
formatting link
Check the main page for what else this company offers. You can really trim Windows down and improve performance and reliability.
Reply to
I noticed some DOS apps that my dad wrote years ago in an special data base language - hum - ran in a dos term in winME. Then dos term in XP nada. That was XP professional grade. Then I opened the directory to do a listing - you know - just look around - executed it and it ran! So that might be some help for the DOS types that lost in an upgrade.
Reply to
Martin H. Eastburn

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