ProtoTRAK Plus loses Zero Datum - HELP

[Ford_Truck_Nut]

Hello, I have a Proto Trak Plus CNC display mounted on a Lagun milling machine. It was made in 1991 and the manufacturer does not know how to fix my problem. Here's how I start for the day. Turn on Prototrak Plus and set zero datums for X,Y, and Z. Then upload a milling program created by Mastercam. It is a simple Point A to Point B mill command on an angle. Upload it by the RS232 port on the back of the unit. From X and Y zero's I start the program from the Prototrak controls. It goes to the point where the milling is to start, and usually says "Set New Z!". Then I am supposed to set my Z dimension to the depth I want and press "Go". This does not happen!! The digital readout change to all zero's and I lose the "Actual" Zero I set when I started the Prototrak up. Southwestern Industries (who makes the Prototrak Plus) does not know how to solve this problem, and only answer is to get a refurbished one for $1043 bucks. The kicker is that that might not even fix the problem!! The display looks like the following picture.......

[DMF_TomB]

with a prototrak plus usually it resets DRO to X0 and Y0 on startup unless you input line number

usually i

1) delete any previous programs from 1 to 999

2) use the prototrak mx2 post processor for mastercam

3) check each line of gcode to see if mastercam code is correct and in the proper SWI format for MX2 mills (2 axis mills) as per the ProtoTrak Plus CadCam interface manual (it is separate or different from the regular operation manual) clearly explains

4) add right after the first line which should say (G20 is inch mode)
G20;
G100 X0.0A Y0.0A T1;

and i add at end before the end "%" line
G100 X0.0A Y0.0A T1;
%

basically at startup i want to be at zero and at program end i want to return to zero
.
if you are using mastercam for generic fanuc 6m post processor after uploading to Prototrak you need to download back to a PC or laptop to see how the Prototrak Plus translated the fanuc.CAM 2 axis gcode.
....... if you used a fanuc 3 axis post processor that gave Z axis commands the Prototrak Plus will usually not translate Z axis commands properly without manual editing

so without seeing what code you are uploading and without seeing what the prototrak translates and downloads it is hard to tell what is happening

[Ford_Truck_Nut]

DMF_TomB, Thanks for the posting. I forget which post processor I am using now, as I set it up a few months ago with help from a Haas CNC operator/programmer. I'll get the info, program, and post it.....just want you to know I should have a post on Monday sometime.

Another thing happened today. The readout started to blink on and off for about 2-3 minutes....then it went blank. I checked the fuse and it was blown. After replacing the fuse and turning it back on....it popped again. I went through four 1 amp fuses before I gave up and went and did something else in the shop.

I was going to program the angled cut using the Prototrak plus controls, to make sure it was not a program problem from the post processor........BUT it started to blink and then it just died. I gave up today.....Monday I'll check it out.

Thanks and have a great weekend!

Wayne (Clifton, NJ)

[DMF_TomB]

if you blow a fuse i would stop and call a factory service rep and have them come and look at it.
.
if it tries to travel too far the control is suppose to stop after 3 to 5 seconds with a fault message and to not blow a fuse. something is wrong.
.
the older trav-a-dial encoders are a fine tooth gear wheel in spring contact with the side of traveling surface or a moving trav-a-dial wheel in contact with a flat surface. if wiper is worn, chips can jam encoder wheel so control senses no movement and can give it full power breaking an end mill.
.
the trav-a-dial encoders are recommended to have yearly maintenance of replacing chip wiper / seals and recalibration. i have seen them go 5 years without maintenance but eventually they will have more and more problems. we had a very old X axis trav-a-dial encoder replaced with a more modern type that has worked very good for years now. the modern types are better protected from chips and dirt.

[Ford_Truck_Nut]

DMF_TomB, Thanks for even more info. I will check the encoder wheels felt wipers to see if they are stuffed with dirt and chips. I'll post what I find. Thanks for all your help so far! Wayne (Clifton, NJ)

[Ford_Truck_Nut]

DMF_TomB, I checked the encoders (X & Y) and there are no major buildup of chips, just a VERY little silver film coating. I have to calabrate the encoders now that I took them off, but that is easy. I have the instructions which I have used before.

I have done very long programs using the Prototrak, and had the same problem lossing zero. After it messed up, I shut it off and came back the next day and then had no problems with it. It is weird!!

Here are the programs I loaded into the Prototrak. They worked fine until the Prototrak was on for a while, so I think it is heat related to the electrical circuits……but I am no expert.

Below is the roughing program using a 1/2” Diameter roughing endmill:

%
PNc30709rough G20 G90;
N100 G101 XB-3.5089A YB-0.5876A XE+13.4911A YE-1.1566A TC0 F10.1 D0.5000 CR-0.0 T1;
N102 ( SET NEW Z! );
%

Here is the finishing program using a 1/2” Diameter finishing endmill:

%
PNc30709finish G20 G90;
N100 G101 XB-3.5084A YB-0.5726A XE+13.4916A YE-1.1416A TC0 F10.1 D0.5000 CR-0.0 T1;
N102 ( SET NEW Z! );
%

The post processor I used in Mastercam was: MPROTMX2.PST

Let me know if you see something that I should be doing different. I appreciate all your help!!

[Ford_Truck_Nut]

I just wanted to let everybody know about the problem I was having with the ProtoTrak Plus. I took the display apart and found a battery soldered to the circuit board. I ordered a battery online from a battery seller, replaced it, and now the problems seems to be gone! If you have any questions, let me know. Contact: fordtrknut-AT-AOL-DOT-COM. Thanks for all your help!!

[DMF_TomB]

good to hear it was just a battery.
.
i am always surprised when they solder the battery rather than use a battery holder so battery would be easier to replace.
.
i leave my Prototrak on. i was told if left off for long periods the battery will go dead faster. my Prototrak Plus is still working ok. i did have to replace a trav-a-dial encoder with a newer style linear scale. the type with ball bearings in a stainless tube. so far after a year it performs far better than the trav-a-dial. the SWI local service rep was able to replace and calibrate it in about a hour.
.
when dro is in incremental mode as it runs program the numbers change and it moves til x and y get to zero.
........in absolute mode on program start (only) often x and y will reset to zero unless program is started at line 1. if you hold button, long enough program will start but reset x and y to zero. i was taught to program it to start and return to x,y zero point. this way there is no surprise about zero reset on program start. when i had trouble with a trav-a-dial encoder the dro was not confirming X axis movement (gear wheel jammed on chips) so it would give it full speed X travel til it registered X axis movement. this would snap off any end mill less than 1/2" very quickly.
........ seeing how my Prototrak Plus is about 20 years old i am amazed everyday it is still working. not many 20 year old computers still running.

[ducati955]

MX3e system. I have the control box, Refurbished Pendant(6 hours use since refurbished)wheel encoders, DNC Key, various cables left over from a upgrade if anyone is interested. Pretty much a total system without the ball screws.
Send email if it is something you could use.
Thanks