[angelw]

Bill, if I understand you correctly, then the cable configuration that uses five wires is the better choice for DNC (i.e., the configuration I am using now), but I should be using hardware handshaking rather than Xon/Xoff.

After so much time fooling with this I want to make some chips before getting DNC to work, but DNC is high on the to-do list.

Al, thanks for the pointer on RS232 monitoring. No doubt it will save me some headaches down the road.

Randall

Hello Randall,
No, your five wire set up is still using Xon/Xoff handshaking. The principal advantage of software flow control is the reduction in the number of electrical conductors between sender and receiver. Given a common ground, only two signals are needed, one to send and one to receive., However, software flow control is not without its problems. Sending Xoff requires at least one character time to transmit, and may be queued behind already-transmitted data still in buffers. Hardware signals may be asserted almost instantaneously, and out-of-order.

It may be that when you get around to needing to Drip Feed (DNC) a program to the control, that you won't have any trouble with Software Handshaking. If a problem is going to occur, it will normally happen when many small moves, represented by a great quantity of data, follows a long move that will hold up the processing of data from the Input Buffer whilst the machine is completing the move. This will ensure that the buffer is full, and if the Uart of the sending device can't react quickly enough to the Xoff, and more than 10 characters are received by the control after the terminate command is specified, then a p/s087 alarm will be raised. Often this problem can be overcome by modifying the FIFO setting for the Serial Port of the External device being used.

Regards,

Bill

[Al_The_Man]

After so much time fooling with this I want to make some chips before getting DNC to work, but DNC is high on the to-do list.
Randall

Generally you will have to enable the PMC output bit G127.5 via a fitted switch.
Depending on the model of Fanuc 0 you may not be able to see the ladder, otherwise if you search for the G127.5 you can see if it is present, it is not always programmed by the OEM into the PMC, it can be done by someone familiar with PMC programming in your area.
http://www.cnczone.com/forums/machin...-o-ladder.html
Al.

[rsfairman]

Something is not adding up for me regarding this discussion of handshaking.

Bill, you said

If you purposely set out to run five wires, your 5/7th of the way to Full Hardware Handshaking, which is more reliable than Software Handshaking, particularly where Drip Feeding is concerned, and is possible with the setting of parameter 0391.6.

but then later you said

No, your five wire set up is still using Xon/Xoff handshaking

The last time I thought about the nitty gritty of serial communication was probably back in the days of the PDP-11 and DEC-20 (i.e., a long time ago) and it was never really my thing anyway, but here goes.

Doesn't hardware handshaking require five wires? That's consistent with what you said in the first quote above; it's what pins 7 and 8 (of the DB9) are for: RTS and CTS. I suppose that I could ask my terminal to use software handshaking (Xon/Xoff), even though these two lines are available, but if I want to use hardware handshaking -- which you point out being more reliable -- then I need the pinout I've given, correct? Are you also saying that I need to set bit 6 of parameter 391 to use hardware handshaking?

Al, it's not clear to me what you mean by a "fitted switch." I can see the ladder (by pressing the DGNOS PARAM button umpteen times), and G127.5 does appear on it, but I have no idea what to make of this stuff. I understand that it's a just a bunch of logical ands, ors and nots that correspond somehow to the way everything is wired, but I don't have any idea what the numbers mean, where to look them up or how to make modifications. I really hope DNC is possible, since there's not a lot of memory built in.

[Al_The_Man]

Al, it's not clear to me what you mean by a "fitted switch." I can see the ladder (by pressing the DGNOS PARAM button umpteen times), and G127.5 does appear on it, but I have no idea what to make of this stuff. I understand that it's a just a bunch of logical ands, ors and nots that correspond somehow to the way everything is wired, but I don't have any idea what the numbers mean, where to look them up or how to make modifications. I really hope DNC is possible, since there's not a lot of memory built in.

Yes i remember building a RS232 card for a PDP11.

The G memory registers in the ladder are used to communicate between the Machine I/O, Programmable Machine Controller (PMC) where all the M,S,T, commands are processed and the part program (CNC) where all the move commands are processed.
They are two co-processors, one takes care of the servo moves, the other the general machine interface, (T.C., Coolant on etc,etc).
The PMC (ladder) is where the machine is told if to DNC, often a switch is wired to enable this in the form of a toggle switch inside the enclosure.
Al.

[angelw]

Something is not adding up for me regarding this discussion of handshaking.

Bill, you said



but then later you said



The last time I thought about the nitty gritty of serial communication was probably back in the days of the PDP-11 and DEC-20 (i.e., a long time ago) and it was never really my thing anyway, but here goes.

Doesn't hardware handshaking require five wires? That's consistent with what you said in the first quote above; it's what pins 7 and 8 (of the DB9) are for: RTS and CTS. I suppose that I could ask my terminal to use software handshaking (Xon/Xoff), even though these two lines are available, but if I want to use hardware handshaking -- which you point out being more reliable -- then I need the pinout I've given, correct? Are you also saying that I need to set bit 6 of parameter 391 to use hardware handshaking?

Al, it's not clear to me what you mean by a "fitted switch." I can see the ladder (by pressing the DGNOS PARAM button umpteen times), and G127.5 does appear on it, but I have no idea what to make of this stuff. I understand that it's a just a bunch of logical ands, ors and nots that correspond somehow to the way everything is wired, but I don't have any idea what the numbers mean, where to look them up or how to make modifications. I really hope DNC is possible, since there's not a lot of memory built in.

Hello Randal,
Hardware Handshaking will probably work with the configuration of the cable you have (5 wires including the RST/CTS pins). My reference to 5/7th is that a Full Hardware Handshake configuration has 7 electrical conductive wires.

Many Series 0 controls have a Tape Mode, even though the machine may not actually have a Tape Reader. If G127.5 arrears in the Ladder and you have a Tape Mode, its likely that you will be able to Drip Feed with your machine using Tape Mode.

Regards,

Bill

[fordav11]

I really hope DNC is possible, since there's not a lot of memory built in.

On Fanuc 0 it is relatively easy to upgrade the memory for a few dollars. Buy some RAM chips, plug them in and change a couple of parameters.
Just be sure to have a full parameter back-up (including the options) and know how to restore it because upgrading the memory will wipe the parameters.
If more memory will allow you to do what you want to do it may be easier than dealing with trying to get DNC working.

Also, FYI, you can get the correct fully wired molded cable on ebay for a few dollars. I bought a new 20-foot RS232 cable on ebay a couple of years ago for about $10

You can buy RS232 PCI card (for regular PC) or PCMCIA card (for older laptop) or Express Card (for newer laptop) for just a few dollars on ebay too.

[Al_The_Man]

I really hope DNC is possible, since there's not a lot of memory built in.

On an allied note, post what you have in parameter 905.
Al.

[rsfairman]

Parameter 905 is set to 0000 0001. Not sure what it means, but that's its value.

Concerning memory and drip feed, I doubt whether a memory upgrade would be enough, unless it will take a megabyte or more. Some of the things I'm interested in doing are more "arty," and that can involve many lines of code. Also, my background is in computer software, so I often write a program (in C, Java, Perl, whatever) that spits out the G-code, which I then feed to the controller. It's not hard to generate 10s or 100s of thousands of lines of code this way.

Which brings up something I've wondered for a long time. How many people out there are frustrated by the fact that you can't really program your machine (milling machine, lathe, whatever)? By "program" I mean using more sophisticated data structures, object oriented methods, etc., and not merely instructing the machine to move here, then here, here, and so forth. Macro B gives you a bit more power, but it still feels like using BASIC on a Radio Shack Model I with 4K of memory (i.e., something from the 1970s).

[memoryman]

That param is PMC-l 3000 step ladder; all bits in 905 are ladder type/size bits.
920.0= DNC1 interface
924.2=DNC2 interface

[Al_The_Man]

How many people out there are frustrated by the fact that you can't really program your machine (milling machine, lathe, whatever)? By "program" I mean using more sophisticated data structures, object oriented methods, etc.,

CAD/CAM improve things over the Gcode method and converts the program to G-M-T code etc via a post-processor.
Check you email.
Al.

[fordav11]

That param is PMC-l 3000 step ladder; all bits in 905 are ladder type/size bits.
920.0= DNC1 interface
924.2=DNC2 interface

he might have meant 901 ^_^

rsfairman, what have you got in parameter 901?

[fordav11]

Which brings up something I've wondered for a long time. How many people out there are frustrated by the fact that you can't really program your machine (milling machine, lathe, whatever)? By "program" I mean using more sophisticated data structures, object oriented methods, etc., and not merely instructing the machine to move here, then here, here, and so forth. Macro B gives you a bit more power, but it still feels like using BASIC on a Radio Shack Model I with 4K of memory (i.e., something from the 1970s).

The number of frustrated people is likely very low, nearly 0. real computer programming is something most people can not grasp or even have any knowledge it exists, especially the average Joe tradesman. sure there are a few people who can and some who know a lot more, but for the majority it is beyond their capability. CAD-CAM is the usual way to program complex parts (PC-based software like MasterCAM etc), or other forms of conversational programming software built into the machines such as FAPT/CAPS/Manual Guide i.
G-Code is remarkably powerful and even complex shapes can be programmed if you know manual G-Code programming and trigonometry. So it's not all that bad :-)

[Al_The_Man]

he might have meant 901 ^_^

rsfairman, what have you got in parameter 901?

Yes I already P.M.'d! him
Al.

[rsfairman]

The value is 1100 0001.

[Al_The_Man]

The value is 1100 0001.

OK it looks like you are maxed out memory wise.
Al.