[midnightrambler]

Hello - I am new to this CNC communications, so bear with me if I sound not all that bright lol.

I have an old Billco CNC1000 XY glass cutting table (mfg 1989). It is being driven by an even older peice of software made by PMC software (1987). It was retrofitted a few years back (2002) with Fagor 8025 controller. The original programming was not updated. It is still running on a DOS platform. It communicates via RS-232 serial port to the cutting table. I have newer software that I am attempting to make run with this table as is. The problem is in making a driver to allow our newer software to talk to the cutting table. Have found manuals to help with generation of Gcode, and used a serial port analyzer to detail exactly how the transmission is sent to the controller. Can reproduce everything except one byte per line. I am told this is a CRC byte.

How does one go about creating the CRC byte for the purposes of transmission? My understanding is that if this byte is not ocrrect, than all lines will be rejected. RS-232 parameters are; Baud 4800, 8 bits, No parity, and 1 stop bit. The transmission that I have trapped looks like this:

Request: 1/26/2009 12:48:35 PM.97764 (+1.9728 seconds)
01 53 4E 53 02 25 36 35 33 30 31 17 4F --------------> .SNS.%65301.O
Answer: 1/26/2009 12:48:35 PM.13764 (+0.1402 seconds)
10 31 -----------------------------------------------> .1
Request: 1/26/2009 12:48:35 PM.13764 (+0.0000 seconds)
02 0A 4E 30 28 33 2E 30 30 43 4C 2B 2B 33 2E 30 -----> ..N0(3.00CL++3.0
30 43 4C 29 0A 17 68 --------------------------------> 0CL)..h
Answer: 1/26/2009 12:48:35 PM.23764 (+0.0501 seconds)
10 30 -----------------------------------------------> .0
Request: 1/26/2009 12:48:35 PM.23764 (+0.0000 seconds)
02 4E 31 50 31 3D 4B 30 0A 17 45 --------------------> .N1P1=K0..E
Answer: 1/26/2009 12:48:36 PM.30764 (+0.0501 seconds)
10 31 -----------------------------------------------> .1
Request: 1/26/2009 12:48:36 PM.30764 (+0.0000 seconds)
02 4E 32 47 32 35 4E 39 39 34 39 0A 17 62 -----------> .N2G25N9949..b
Answer: 1/26/2009 12:48:36 PM.38764 (+0.0501 seconds)
10 30 -----------------------------------------------> .0
Request: 1/26/2009 12:48:36 PM.44764 (+0.0601 seconds)
02 4E 31 30 30 28 4C 41 59 20 31 20 43 55 54 20 -----> .N100(LAY 1 CUT
31 20 20 20 31 20 4F 46 20 20 37 32 78 31 32 30 -----> 1 1 OF 72x120
20 33 2E 30 30 43 4C 2B 2B 33 2E 29 0A 17 0C --------> 3.00CL++3.)...
Answer: 1/26/2009 12:48:36 PM.59864 (+0.0501 seconds)
10 31 -----------------------------------------------> .1

The second last character in each request line is the ETB code (x17), and it is followed by this one extra byte of data, which my programmer tells me is a CRC code (I am also a programmer, just not familiar with CNC, PLC, or serial communications). How do I go about determining the correct CRC value to include in our new software's transmission?

I have spent hours looking for on-line documentation that may point me in the right direction to no avail, and cannot get my hands on a DNC 25/30 Protocol Manual, which I think would have the answer for me (discontinued from FAGOR).

In addition, I would like to know about the answer line shown in the above sample, is shows the DLE code (x10) followed by a rotating 1 or 0. I am assuming that this is a simple confirmation of the previously sent request, and the 0 and 1 are just alternated states... indicating transmission OK. Am I correct on this?

Hopefully I can complete this software change over with the answers to these questions.... Any help is greatly appreciated.

[kcho]

Hi you have for free windnc, the Fagor communication software. This CNC it´s online with the software. If you want to pass the programs with no dnc fagor protocol. You have to go to the pheripherical mode. Wath do you want to do? You need to run an infinite program or only pass to the CNC?

Carlos

[midnightrambler]

Thank-you Carlos... very helpful, saved me a ton of time.

Have tested this out and it does everything I want it to as is, however, it is possible to call this program on a command level from within another program or will it only work as a third party program. I can work with it as a third party peice of software but it would be cleaner if I could embed the appropriate commands within my own application thereby making it a single step process for the machine operator.

thanks again

[kcho]

Ok, you have to be patient with me I am Argentine and I don´t understand all the expresions. So if I right you want create the protocol for your software. I found a pdf where explains the DNC protocol I m going to attached the document.
Let me know what´s happend with your software and I like to have a copy of it always you want to. I´m Fagor Oem and maybe it could be usefull for me.
Sorry is in Spanish but you have the diagrams I´m sure you will understand it although you can ask to me, I don´t have any trouble to help you.

Carlos

[accellodyne]

I have a Fagor 8020 communications protocol book. I could copy it for my costs at Staples for anyone who would be interested. I have two machines w/8020's and use Fagor DNC 3.02 software to feed them both "infinite" (drip fed) programs with one PC simultaneously. I use OS/2 v3.0 on a 20 mhz Zenith 8-bit computer. I also use fiber optic RS232 links to connect the machines to the PC to isolate the TIG welding in our shop.