Fanuc 087 alarm, drip feed Xon/Xoff handshake

[tsmith5411]

I have a router with a Fanuc 21i-M control and I am trying to drip feed programs using ProNC software. I am using an RS232 cable to communicate; 9 pin at the PC and 25 pin at the Fanuc. I can transfer files to the Fanuc memory without issue but I continue to get an 087 Buffer Overflow alarm when drip feeding programs too large for the Fanuc memory. It will run roughly 30% of the program until the buffer becomes too full and then it triggers the 087 alarm. I have slowed baud rate to 4800 and turned off FIFO buffers after reading that suggestion in other posts. I was able to add data packet delays and character delays which gave me a round-about way to run the program but it is not a sustainable solution. I believe my true issue is with the Xon/Xoff handshake. I have Xon/Xoff set as my flow control on the ProNC software and on the COM port in the device manager on my PC. I believe that the Fanuc is not sending an Xoff signal or maybe my PC is not recognizing it. Is there a way to test the handshake or a solution to my drip feed issue? Any help is appreciated. Thanks.

 

[Vancbiker]

Switching to hardware handshake and the appropriate cable is the most reliable method for drip feeding.

Are you using a USB to serial port adapter? Those often are troublesome when relying on Xon/Xoff.

 

[tsmith5411]

I am not using a USB to serial port adapter. How do I go about setting up the hardware handshake? I see an option for this on my PC device manager and inside of ProNC I can change the flow control to RTS/CTS but I am not sure how to set up hardware handshake on the Fanuc controller.

Is there a different cable that I need to use?

 

[Vancbiker]

I do not have a 21i to verify this information taken from the parameter manual…

Parameter 20 shows which I/O channel you are using. Parameter 102, or 112, or 122, or 132 sets the device type for each I/O channel 0-3. You probably have a 0 set to whichever channel you are using. Change to 4 to use hardware handshake.

For the cable, 9 pin to 25 pin…

2-2
3-3
4-6&8
5-7
6-20
7-5
8-4

The settings in your DNC software should override the settings in Device Manager.

 

[tsmith5411]

Changing parameter 102 to 4 did it. Thank you for your help, we're cutting parts again.