Most encoder disks are encapsluted in plastic or glass. I guess it's possible that some manufactures cheap out by only printing on one side, but I've never come across it myself. If you hang a scope on the output, you should see if the pulses are clean or not.
John Barnes
jb-laser@telus.net
Originally Posted by JB Laser Tech
Thanks for the info, but IMHO I don't expect dirt/debree to be causing any problems (not that it can't). The encoders are new and I pulled the cover and inspected them.
I guess I shoudl explain a little more becuase this may sound like I am kicking on the US Digital encoders and I do not mean to do that. In fact these encoders really seems to be working very clean. WHen I have the problem it is at a very high RPM point and it may even be at a higher point than my motors will be able to run when they are loaded.
I did run the scope on them last night and the signals are very clean (so clean I could not believe it) and they would run without any inconsistancy what so ever in the range I was runnning them.. Now I did have my rapids limited below the point that my problem happens so I didnt get to see if the encoders where the cuase or not. I will set my rapid limit up above the point I have problems at and see what is happening the next time I run the system (maybe tomarrow).
The info from some post here lately indicate that these encoders can not drive a 6 foot cable. When I mount my system (its still on a bench right now) I may have to add cable lenth and I expect I will have to add line drivers then. I may add them no matter what just so I am sure that the signal strenth will stay strong. Hopefuilly this might be whats happening when I do have problems and the line drivers will cure it so I will be able to gain a little more RPM for my rapids.
The gear/belt drive ratio that I use on my screws will effect what rapids I end up with also. Right now I plan to use 4 to 1 gearing because it allows me to run a very high ressilution and the system seem to run very smooth this way. It also keeps my motors at a higher RPM and that is where the servo's seem to shine. Of course I would like to achive as high a rapid as I can but good response in its cutting range is more important IMHO. These motors are very strong though and others are running 2.5 and 2.8 gearing ratio and there claims are they have very good response and power. I would really like to see video of these system becuase I feel like some of the work I willl be doing it would be better to have good quick response when changing directions adn this will be more important than fast rapids. If I was to run a 2.5 gearing I can reach 275 rapids with no problem, but the system does seem to work better with the 4 to 1 ratio figured in. I may get one setup of each and give them both a try. Testing on a bench just doesnt tell the whole story so in the end I want be able to answer these questions for myself until its mounted and ratios are tried. Either way if I can cure this one problem I am having it will allow more rapids no matter what gearing I use, and if I cant cure the problem its not like I will be hurting for speed no matter which ratio I chose. Cutting performance is the goal anyway but I do intend to add a auto tool changer so rapids should be considered.
When I did the testing with the scope all my signals where very clean and uniform. I am kinda surprized with this because I am running floating grounds and that seems to be a no no in some cases. My break out board does require the grounds floating on it though so there is not much I can do expect run all good shielded cabling, which I have. The next couple of days should give me some answers on all this and I can make the changes to help it.
As far as the US Digital encoders I can't complain about them in any way at this point. There signals are very smooth and clean even though they are the HEDS E5 modules that are claimed to be week. If it does turn out to be them causing the problem then a $20.00 line driver should cure it. If it doesnt cure it (if there the problem) then like I said its not like I will be hurting for speed anyway.
Thanks Jess
Lucky, I re-read back and saw your question and remembered with the Oh yea then checked on what I'm running. I have 300 set in the mach debounce entries and the equivalent setting in SS is # 143 ? anyway the note says multiples of that number and so i just put in that number ! I think I could zero them all out now as my system is running cleaner than I have ever experienced it before. In the last few days I have re set my column, head, spindle alignment to the best I could get. not much has changed. I also loosed my Z gib a touch and tightened the x & y each just a touch. Again didn't need much change. I also did some parameter changing within my Hitachi L200 to shorten the accel decel times, then I started making some chips again. Today I even programed my tapmatic into the job I was running and expecting to snap a few taps but it actually worked for me first crack, didn't need to put in the old sacrificial tap after all ! But since I was running a 4-40 form tap I didn't want to bash as I only have two of the little buggers. The only issue I have left now is that my vfd occasionally faults out on M5 but I think incorporating the breaking resistor I have for it will solve that as it only occurs after warming up. Problem is I don't have a good clue yet how to wire it in properly yet. Any suggestions ? The heavy wires I assume replace the jumpered terminals but I don't know what to do with the light wires yet ! It looks like they go to the source terminals, but I don't get it !
later !
Don
IH v-3 early model owner
Cruiser I cant say I have ever even had a VFD in my hands, but looking at the manual for the one you listed it doesnt seem to awfully bad to wire up .
If I understand it right it shows using the PD/+, PD/+1 and the N/- terminals to hook that up. The resistor goes across the PD/+ (big wires), & N/- terminals. The other part goes across the PD/+ & PD/+1 terminal.(little wires)
I may be totally wrong here but thats what it looks to me like.
Jess
I'm going to post something in the proper area and try to get some experienced help on this one. On my info I don't see the PD etc terminals at all. I am using the L200 015 vfd and have the JRB-120-3 breaking resistor, I suspect It is a simple thing but I don't trust my interpretation of the schematic supplied and don't want to make a mistake with the 220 power supply.
Don
IH v-3 early model owner
I have received Information from "Driveswarehouse" by "Babu G'Vam" In how to accomplish my task of dynamic breaking and the L200 vfd ! It is posted with a new shopping list in the > http://www.cnczone.com/forums/phase_converters_vfd/ < link with as much detail as I have available @ this time. It all boils down to not having enough knowlege to make an informed purchase ! $ And the cost goes up $
Don
IH v-3 early model owner
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