Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Jeff_Birt on May 29, 2007, 08:42:50 PM

Title: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on May 29, 2007, 08:42:50 PM
I tired to respond to a old thread (http://www.artsoftcontrols.com/forum/index.php?topic=2570.0) on this same subject but it does not seem to show up properly so I thought I would start a new thread.  The subject is retrofitting a Bridgeport Discovery 308.  While it's basically in good shape the control is shot and no parts are available, etc.  I would like to keep the drives etc, but the drives have analog inputs.

I have the same mill in my lab that we are giving to another department and I am going to retrofit it for Mach III for them.  From reading the above mentioned post and other posts about the Galil 18x2 boards and Grex, it looks like the Galil might be the way to go. The Grex analog outputs are only 8 bit resolution so I would have to us it's SD outputs and something like Pixie's to control the analog drives.  Considering that fact that both the Pixie's and Grex would want acccess to the encoder signals, I can't see how that would work; please correct me if I'm wrong. (I did email Gecko to see what they say  ).

Here is the cost breakdown of both options as I see it:

Gecko:        $400                                  Galil: DMC-1842         $1200
Pixe's: (4)      320                                  64 bit I/O expansion     200     
                   ------                                                               ---------
                   720                                                                  1400

So from a initail price the Galil is about twice as much but the Grex might not be able to do the job, any input?

Thanks,
Title: Re: Bridgeport Discovery 308 retrofit
Post by: chad on May 30, 2007, 02:16:03 AM
The grex doesn't care about the encoder inputs. I doubt it ever will. The Pixe's and a grex should work fine. ( I haven't tried it yet.)

Brian would be the one to ask about the Galil. He is the one working on that.

Chad
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Brian Barker on May 30, 2007, 07:54:16 AM
I ordered a galil to have here for testing and I HOPE to have it in a few weeks :) I want to add rigid tapping with the Galil!!! that is about the only reason that have ordered it ;)

Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on May 30, 2007, 09:21:34 AM
Quote
The grex doesn't care about the encoder inputs. I doubt it ever will. The Pixe's and a grex should work fine. ( I haven't tried it yet.)

Hmm...that's curious as the G-Rex description PDF says...(the inputs are also described in teh programming manual)
Quote
2) 6 quadrature encoder inputs including index channel. Maximum encoder count rate is 1 MHz. Encoder inputs are filtered and have indicator LEDs on each input.

So, am I to understand that this functionality is not available/utilized with Mach III at this time (or ever)?  You still set accel/decel and velocity withing the G-Rex, correct?  And, I guess if the G-Rex does not handle the encoder inputs it is runnign in open loop mode making the Galil boards the only current choice for closed loop operation?  I would also like to hear from anyone who is succesfully running a Galil board.

Thanks for all teh help guys, just trying to get this all striaght in my head.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: vmax549 on May 30, 2007, 06:27:06 PM
Perhaps I am confused but if the servos/drives are ok all you would need to do is install the pixies to the drives and hook up to the lpt ports????? The LPT's are hard to beat in form and function.  The servos are closed loop at the servo drive level and can be setup to stop the program if the error level is tripped. True closed loop error correction at the controller level is very complex and is rarely needed.

If the drives are bad then all you need is the gecko's/powersupply and hook up to the LPT ports

Keep it simple  (;-) TP
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on May 31, 2007, 12:38:15 AM
I'm just rying to consider all the options.  Mach works great with a single LPT on my Dyana 2400.  The Bridgeport has MANY more requiments such as, tool changer, more limits, enclosure safety switches, spindle control, probing, MPG and etc.  Now if I went the LPT route I would need at least two LPT's, two breakout boards, 4 Pixies, and likely a PLC to handle the tool changer or other auxillery functions.  Add up the cost and complexity of such a system and your in the same ballpark as a Galil, the G-Rex however seems to have 90% of the lower cost Galil board functions, for 1/3 the price.  I would only slightly disagree with you on the necessity of closed loop operation, I would not say it is 'rarely needed', but rather 'it is not always needed', it all depends on what the system is designed to do.  (But then I could be picking nits  :) )

So, if anyone is really using a Galil board how is it working for you?  Are you closing the loop?  Are the encoder inputs really used on the G-Rex? I have emailed Gecko but not heard back yet, guess I'll try calling tomorrow.

Thanks again to everyone for all the help,
Title: Re: Bridgeport Discovery 308 retrofit
Post by: vmax549 on May 31, 2007, 12:52:26 PM
Hi Jeff,
I am running a series 1 boss Bridgeport , 4axis,mpg, probe, spindle control,modbus, on 2 lpt ports with a lot of extra inputs/outputs leftover. I do have a closed loop at the drives, if it exceeds the tolerance it signals Mach to stop. It just does not do online corrections with mach. I don't think any other low end controllers do either. I really think it could handle a tool changer with no problem, but the qc30 spindle is not easily adapted to tool changing. Keep us informed on your project, it is always exciting to see a new project starting up. I usally learn something following a project such as yours.
 (;-) TP
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on June 04, 2007, 04:58:21 PM
after a bit more research I find that the Discovery 308 requires the following I/O:

19 GP inputs (18, digital 1 analog)
15 axis specific inputs (encoders and limits)
13 GP outputs
4 Axis specific analog outputs (drive command signals, or could be generated with S/D converter)

So it looks like I could get by with a G100, I am still unclear on how/if it works with S/D converters but am attempting to find out.

I still like the idea of the Galil PCI card, but will have to do a bit more reading on it.  Which ever route I go I'm sure that that the Mach III crew will be there to help out.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Brian Barker on June 05, 2007, 09:41:11 AM
The G100 is working but only in Exact Stop mode :( CV is not working at all on my mill... I know Steve will get this fixed... I just don't know how long it is going to take him.
The Galil can do all the IO and will not have a problem with the CV but I would need to know more about your application and the parts that you would like to make before I can recommend anything :)
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on June 05, 2007, 11:16:29 AM
The type of parts, that's a tough one....the machine is going into a university machine shop setting.  It will be used by a limited number of students to make parts for student design competitions.  So, stuff like hubs for the solar car, parts for robots, etc.  They have no CNC machines presently so we can live without features that may not be working yet like, rigid tapping or CV mode.  Clear as mud?

What I'm most concerned about is system complexity.  Although the G100/Pixies may work fine the route of Mach III -> G100 -> Pixies -> Drives is more convoluted than Mach III -> Galil -> Drives.  Simpler = Better
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on June 07, 2007, 02:37:18 PM
After talking with Brian the other day it seems that the best way to go on this retrofit is the Galil route.  Everything we need to do with the machien can currenty be done with the Galil and 64 I/O extesnsion board.  The cost diffrence between the two options is only in the $600 range with the Galil provideing the least complicated finished system.

I've downloaded all the Galil docs I can find and have been reading like crazy.  I was specing out the computer parts wich will be mounted in the same large enclosure as the original 80286 MB' this cabinet also contains the drives and other bits.  It occured to me that I'll need a way of securing the Galil PCI card and video card.  I've seen other have stripped an old PC case and used that.  I have an old case that I could use in the same way.  Does anyone knwo of anyother options?  Something like a mounting panel for the MB that has a riser to hold the cards?

Thanks,
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Chaoticone on June 07, 2007, 03:06:18 PM
Hey Jeff,
    As far as mountig the Galil, You should be able to bend the tab at the bottom and screw it through your panel you mount the MOBO to if the stand-offs aren't too long. I used 4-40 X 1/8 stand-offs to mount my MOBO.

Brett
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on June 07, 2007, 11:37:03 PM
I spent some time looking today and can't belive that no-one seems to make a simple MB mounting tray.  Check out the slide out MB tray in this small case: http://www.tigerdirect.com/applications/searchtools/item-details.asp?EdpNo=1800611&body=MAIN

That would be perfect, to mount a tray like that inside the enclosure.  It might be worth buying the case for the tray and power supply.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Chaoticone on June 08, 2007, 06:06:35 AM
A good friend of mine just used one of those about 2 weeks ago on a retrofit, Cam Tech. I like that little case a lot. I just got my new cabinet put together with slide out panels. It works good but was a pain to wire. LOL Here is a link to mine.

http://www.artsoftcontrols.com/forum/index.php?topic=2994.10

I need to get some pics. posted of it all wired up. :P

Brett
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on July 23, 2007, 04:49:10 PM
Finally got the parts in the end of last week (had to wait until new fiscal year here at the University to buy stuff  :( ).  Got the Old unneeded stuff stripped from the control cabinet, the PC built and started to mount the new bits.  I bought a Ultra MicorFly case/mobo combo from TigerDirect.  After building the PC and loading Mach III, and a quick driver test (hey, even the built in graphics work good!), I took the case back apart.  The removable mother board tray was pulled (you can see the Galil card in the pic).  The tray will be mounted on the bottom-left side of the cabinet in the same area as the original PC-AT mobo.  The mobo will wind up mounted so that the 'back' will be pointed down (but it will be 8" or so off the cabinet floor).  This will let the 100 wire Galil cable travel neatly up the back corner to the IC-2900 (a terminal board for the Galil) which feeds from the back.  Where the big green board (SAF board) was removed from the center of the cabinet two 16 position Opto-22 racks will be mounted (the hold 16 opto-isolated Solid state relays, either inputs or outputs).  I had the Opto-22 racks, and they fit perfectly.

Title: Re: Bridgeport Discovery 308 retrofit
Post by: Brian Barker on July 25, 2007, 10:20:26 AM
Looking good :)
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on July 26, 2007, 03:43:25 PM
I got a bit more work done today.  The side panel was removed from the machine and fitted with the new mobo, ICM 2900 (breakout board for Galil board) and places for two 50-pin ribbon cable breakout boards (made by Phoenix Contact).  I made a angled bracket from some 1/16" x 1" aluminum angle that mounts to the rear of the motherboard tray (and cut couple tabs out of the scrap) to mount the motherboard to the side panel.  It worked out pretty good allowing the motherboard to be removed with four thumb screws (the former case screws).  I had to remove the wire duct shown on the right of the side panel as it was way to tight in the corner.  The 64 point I/O extension from Galil uses two 50-pin ribbon cable connectors, so I'm running a ribbon cable from the Galil I/O board to the  Phoenix Contact breakout board.  I can then run separate cables up to the two 16-point Opto-22 racks. I still have a spare 32 I/O points ans the place to mount another breakout board, just no place to mount anything else  :).

Title: Re: Bridgeport Discovery 308 retrofit
Post by: RV on December 28, 2007, 12:33:57 PM
Although I am not using MachIII, this looks like the best place to find some help.  I too am doing a Bridgeport Discovery 308 retrofit, I will be using Vital Systems' MOTENC Lite PCI card (8DAC, 8ADC, 4ENC version) with their analog breakout board to control the MSI servo amps for the 3 axis drives; the remaining 4th axis analog control will be for spindle control.  The spindle motor controller is a V400 Flux Vector Drive by Control Techniques and the input requires a serial interface with RS485 protocol. 

The question I have is what has anyone else done for the spindle control or its communication for a retrofit such as this?  I have considered a signal conditioning circuit with the use of an ADC and a comminucation interface such as a Phillips SCN2661 (CI used in the original machine circuitry).  I don't mean to hijack this thread but thought this would be an appropriate place for this information and maybe spark some more updates or input from the existing Bridgeport retrofitters.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: Jeff_Birt on December 31, 2007, 12:41:31 PM
The spindle drive can bet set to accept 0-10V signals as well. In the original machine while milling the spindle drive runs in RS422 mode, basically just getting the speed command. The drive uses separate encoders for velocity feedback (this encoder goes to the drive) and position (this encoder goes to a little circuit board beside the spindle drive). When doing tool changing, the spindle drive is set to 0-10V mode and another circuit board takes over to control. It supplies the analog reference and reads the secondary spindle encoder signals to properly position the spindle for tool changes. I have retained this original setup, but I think it would work just as well, perhaps, to run the spindle drive the whole time in analog mode. But, by retaining the original setup I have a spare 4th axis to use for a indexer etc.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: RV on December 31, 2007, 02:32:05 PM
We acquired this machine in a non-working condition, so I am at the disadvantage of not having seen it in action.  I am at the mercy of the Installation, Parts, and Maintenance Manual to provide the descriptions of what the machine is supposed to do and how it accomplishes those functions.  Unfortunately there are some key misprints in the manual and I believe I may be hung up on one now.  In the description for Parameter 18 (Analog Speed Input Scaling) of the spindle drive it states the default is "6-- rpm/volt" I read this to mean 6 rpm/volt or 60 rpm=10V and assumed it was set at this value to achieve better low speed resolution for 0-10V analog signal from the orient card (tool change positioning circuit board) and would not work for regular milling rpms.  After closer inspection I see that it also states in parentheses that 6000 rpm=10V and must mean that the default setting is 600 rpm/volt.

If it can be confirmed that parameter 18 is left at its default setting of 600 for both normal run and tool change control functions then I will be off and running with it set to use the analog reference for all spindle speed control.

The serial connection was also used to monitor and set a number of the spindle drive's parameters and bit parameters, will I need to retain the ability for the serial connection to monitor and/or set any of those drive parameters in real time?  I see the important ones such as enable, reset, zero speed, drive at speed, external trip, etc. are all hardwired 24V logic I/Os, is that all I will need for full control and functionality?

Thanks.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: FarReachFarm on March 18, 2008, 10:48:31 PM
I am *so* excited to hear about the 308.  I have a 300, same thing only it has a skirt-enclosure rather than fully enclosed and it does not have a tool changer -- I think the vector spindle controllers are different, mine is a Control Techniques (which now new because the old fried).  I  did the Galil based retrofit about 7+ years ago -- yes I've been making stuff.  I've used Mach 2 before and loved it but Galil support wasn't available so I went with Camsoft.  I don't like the Camsoft S/W I bought (I'll spare you the reasons, there are *many*), so that's why I'm excited that I happen to notice Mach 3 supports Galil!

I bought my machine on eBay (has all the original manuals and wiring diagrams), it was in great shape mechanically, but the controller board worked for a few days then fried due to damage during shipping (PCB cracked).  I decided to retrofit it -- My conversion consists of a Galil DMC-1850 (5 axis), Opto-22 (ISA card), Camsoft dial pendent (which I like a lot), Advanced Motion Control servo drivers, the original servos and power supplies, new Control Techniques vector drive (because the original decided to no longer accept commands via the +/- 10v signal line or RS 485 command interface) -- oh and Camsoft Pro (nightmare started & ended there).  I'm using a 486 PC running Windows 98, although I have an XP OS on a removable drive. I had to choose a 486 because at the time 486 boards still had ISA slots (now there are 586 boards with ISA) for the Opto-22.  On other projects I've used the Opto-22 Snap Ethernet system (way cool).

I bought the Galil WDSK tuning program from Galil to figure out the PID values and wow(!) the machine achieved fantastic accuracy.

Looking at Jeff's wiring I was happy to see that we made similar changes, quite validating.

I have *so* many questions about the implementation of Mach 3 for Galil.   

Some of the questions I have -- I haven't read the entire forum yet, just getting started with Mach 3:

Set up of the brake release on the Z axis?  I have it wired to the servo driver so when the driver powers up the brake is released (no S/W as that is quite dangerous by itself, I found out the hard way).  So now when the driver turns on, there's a delay before the servo is fully energized to hold the weight of the head, thus the Z-Axis "bounces" for a moment.  I figure a delay timer of some sort might work -- suggestions?  Once energized the Galil postions the Z correctly after the bounce, but this sudden movement cannot be good for the servos.

I'd like to know more using the Opto-22 with Mach 3 -- I'm not sure how to interface the Opto-22 with Mach 3:  Right now, in Camsoft, I use it for low-air pressure detection, low oil lube level, tool load/release, controlling the light inside the tool load/release button.  I have SSRs for other things, but not hooked up... I want to use it to turn on the coolant motor (1amp), but I'm concerned about burning up the SSR.  I had this happen once on another Opto-22 system (ethernet) the drove a solenoid for a hydraulic pump valve (toasted the solenoid and SSR) so I used a mechanical relay between the SSR and the solenoid.  One of my questions is that even though the SSR is rated for 110v and several amps, can it really handle the spike load when the motor starts and the operational load?

In Camsoft, I had to write a lot custom scripts (in this really strange language) to control and detect things (plus fix a lot of other issues such as spindle drift and incorrectly implemented g-codes).

I'm interested learning about tool eject customization too (via Opto-22 or the I/O ports on the Galil).

Implement rigid tap cycle?  My machine does have the timing pulley on the spindle, but it not connected to an encoder (need to fabricate the bracket), which the 308 does use an encoder.  I'm thinking of adding the encoder for rigid tapping.  Currently I use a spring loaded tap holder, works great, but rigid tapping would be great.  Also the encoder would allow for spindle alignment so it's easier to load the tool.

Digitizer probe anyone?

Any info or pointers to forums would be GREAT!  Thanks!

BTW: I'm in Seattle I also have met some of the original folks that repair and actually worked on these machines back in the UK.

--Scott
Title: Re: Bridgeport Discovery 308 retrofit
Post by: FarReachFarm on March 18, 2008, 11:04:44 PM
Oh I forgot to memtion that I "articulated" the arm that holds the monitor and keyboard -- cut the arm, welded in a joint, this gives me more flexibility in the small space I where I had to place the machine.  The CPU is in a conventional tower box, shock mounted on top of the control cabinet.  Although I prefer the solution with the PC inside the cabinet as shown in the pictures in this forum.
Title: Re: Bridgeport Discovery 308 retrofit
Post by: JHChoppers on July 24, 2008, 12:05:12 PM
I am also interested on how things will work out with your 308s.  We plan to retrofit this BP 412 with Mach3 also

(http://www.jhchoppers.com/photobucket/mach3/bp_412.JPG)
Title: Re: Bridgeport Discovery 308 retrofit
Post by: FarReachFarm on July 27, 2008, 01:08:48 AM
Hey JH and everyone else on the forum!

Well I'm *finally* back in the game, have not worked on the machine for months -- b/c Grandma got cancer, I took new job prototyping new cell phones, had house repairs, oh... and my wife bought goats & sheep.  If that's not enough info for ya, then email me... :-P 

Most importantly, when the window of opportunity opened I needed my card upgraded super quick --> I owe great thanks to Galil for upgrading my DMC1850 (very early serial number) so it will work with the newest drivers.  They turned it in 3 days, which included shipping, for an awesome price of only $75 (so I bought the tools too).  Saved me from spending $2000+ on a new board -- gotta love THAT.
Tomorrow, we'll get the board installed run the (new) servo design kit s/w to tune the sevro loops and then try Mach3 again.

My old BP Discovery 300 (named Bridgette) will spring into life this weekend!

After that I'll crack open the plug-in S/W to continue developing & testing code to monitor lube level, air pressure, and load/eject tools.  Once I have it working all share the code.  I'm attempting to do this w/o writing any custom Galil machine code.  I'll share when it's stabled and safe.

There are 3 projects on the docket -- completely different than the last set I listed.  Cell phone accessories, new type of snow board binding system, and a mechanical calibration system for RC helicopters. 

--Scott
Title: Re: Bridgeport Discovery 308 retrofit
Post by: JHChoppers on January 06, 2010, 04:05:34 PM
Any progress on the 308?

I started on my 412
http://www.machsupport.com/forum/index.php/topic,13365.0.html (http://www.machsupport.com/forum/index.php/topic,13365.0.html)

Thanks,
JH