HAAS RS232 doesnt work - random errors

[GITRDUN]

Just installed a 94 HAAS VF-1 and plugged it up to my stand alone PC in the shop to upload all the program files and it just aint happening. As of two days ago i had a Yasnac controlled machine hooked up to the PC to send programs and had no problems. I have it hooked up to my Fanuc controlled lathe and it works fine as well. But for some reason the HAAS is having fits trying to upload to it. It either hangs on the "loading" or it throws up an alarm when you send the program. The alarms vary but most common is unrecognized code or no program number. Once in awhile it will actually load fine on a very short test program like 10 lines in length. But then if you send the exact same program again after deleting that program from the machines memory it goes back into all the problems of hanging at load or throwing up varying alarms. Its just totally random and im about to pull my hair out trying to isolate the problem. I have everything in sync as far as baud rate, bits and so on. Ive tried different bauds, paritys, and everything i could think of. I changed the PC port to be in sync with the machine and the software. Even used a null modem cable and get the same results.
I need some help fast, i got to get this thing running and i dont have time to manually program every program one by at the machine control.

[gar]

060920-0636 EST USA

GITRDUN:

Check NOISE and GROUNDING at my web site www.beta-a2.com .

That will give you some background information, but it is better if you call me at 734-930-6136.

.

[1ctoolfool]

it might not be much help but you must have a % at beginning and end as first and last character and program number format Oxxxx.
Our VF-E will reject programs from the floppy without these format characters.
good luck,
joe v.

[GITRDUN]

Talked to a HAAS tech on the phone today and think we might have the problem figured out. He says a low voltage from the power supply to the comm board will cause random errors when uploading but will still allow it transfer out to a PC without trouble. Ill have to check the voltage coming out of the power supply tomorrow and see if thats the culprit. If thats the problem then the only sloution will probably be to replace the power supply.

[Dan Fritz]

Haas controls are notorious for ground loops. We have used opto-isolators on these troublesome Haas controls with good results. A surge supressor will not do the trick, it has to be an opto-isolator.

Not all Haas controls have this problem, but quite a few of the older ones do.

[gar]

060923-1554 EST USA

Dan:

We make and sell optical isolators for the purpose of isolating the ends of an RS232 communication link. This isolation breaks the ground path which virtually eliminates ground noise problems, and provides equipment protection from damage up to about +/- 2000 V peak. Additionally we have low impedance drivers that allow in most cases communication at 115.2 kbaud at 4000 ft.

I believe the bigest ground noise problem with HAAS originated about 1996 with the introduction of brushless servos.

Shortly after GITRDUN posted his message I talked to him for a long time on the phone. It did not appear that he had a ground noise problem, a problem in the transient limiter behind the DB25, or in the ribbon cable to the communication board. What it looked like was a HAAS problem in the CPU area. The problem only appears when HAAS is receiving RS232 data. No problem sending.

We have not heard back on what voltages the HAAS power supply is producing. But HAAS did not ask for a check on AC ripple voltage. Off hand I would doubt the power supply is the problem because the machine does not appear to malfunction in other ways.

This appears to be a problem that is not easy to solve without board substitution.

.

[GITRDUN]

Got the problem solved finally.
It turned out to be a problem somewhere on the processor board. We had to replace the board with a new one after another problem arose. After installing the new board the RS232 works perfectly. Got lucky.