[merrittr]

Hi All,


I have a problem that when I connect up a fanuc 6t to a computer rs232 port neweere than a 486 I get a rs232 error even though the port settings are identical 7,2,e . Is there some magic that needs to be done to make newer rs232 ports act like older ones?

[dcoupar]

What error are you getting?

[merrittr]

the error is
86:Reading output by the rs232 interface , a transmission or I/O device problem occured.

this happens as soon as we bring 6tb-2


input read on the console of the CNC with the 6tb-2 controller in it. However if the connection is to a older computer (anything less that a pentium) it works and does not give a RS232 error.

[Vega Bill]

Hi,

The newer PC's have FIFO (First In First Out) buffers on the serial port chips. Fanuc
systems have a very small buffer (about 12 characters). If the Fanuc issues an XOff
and the transmission is not halted prior to filling the Fanuc buffer the control will issue
an error.

You can disable the FIFO buffers on most serial ports by going to Control Panel, System,
Hardware Tab, Device Manager, Right Mouse Click on the Serial port and select Properties.

Go to the Port Settings Tab and press the Advanced button. If the serial port has
FIFO buffers, uncheck the Use FIFO buffers checkbox.

If that does not work, you may have to change your communications program on the
PC to one that uses a polling method for transfering files.

Hope that helps

[merrittr]

Hmmm good info to know, didnt/seem to help it for sure is the hardware because I dont even fire up the mastercam software (or the custome software we have written). As soon as the General Numeric CNC is put into read mode we get the serial error

[Dan Fritz]

The Fanuc will throw an alarm 086 if it does not see a "high" signal on pins 6 (Data Set Ready) and on pin 8 (Data Carrier Detect). Normally, we just wire the cable so the pins 6, 8, and 20 are all jumpered together on the Fanuc side. Pin 20 on the Fanuc is an output signal (Data Terminal Ready). When you press PUNCH or READ on the Fanuc, it turns on pin 20, which then turns on pins 6 and 8 through your jumper. Problem solved.

If you're using a commercially made "Nul Modem" cable, or a Nul Modem adapter of some kind, you probably don't have a jumper from pins 6 & 8 to pin 20. Instead, your cable probably connects pins 6 & 8 on the Fanuc side with the DTR signal on the PC side. If this is the way you're wired, then you must open the COM port on the PC side before trying to PUNCH or READ on the CNC side. If the DNC software does not have the port open, you won't get your DTR ready signal, and pins 6 and 8 on the Fanuc will be off, so you'll get the alarm.

Here's the cable wiring diagram that works for us:

Fanuc side (25-pin male) ---------------- PC side (9-pin female)
pin 1 --------------- cable shield
pin 2 ------------------------------------- pin 2
pin 3 ------------------------------------- pin 3
pin 5 ------------------------------------- pin 7
pin 7 ------------------------------------- pin 5
pin 6 -----
pin 8 ----- <-- jumper together
pin 20 ----

Alarm 086 is almost always due to pins 6 or 8 not being on. Alarm 087 is usually the "Buffer overflow" alarm that happens because of the FIFO buffer problem mentioned by Vega_Bill