[00:00:52] <frallzor> http://pici.se/p/qRVwMCSxV/
I want to do this in mdf, how to make it stronger?
2750x1830x16mm all in all
MarkusBec_away is now known as MarkusBec
Put it on a stiff backing
the link shows a slotted substrate sheet yes?
where 1 is made into the slots
20 smaller bits
and you want the sheet to be stiff? Or "strong". strong is not sufficiently descriptive
so it can be used as good as possible to clamp sheets of workpieces to it
such a substrate would be useful for attaching workpieces or stop blocks
yes I know =) thats the plan
but can will MDF cut it?
If the material is MDF, pull out might be an issue, Glue on an overlay of sheet material such as formica (laminate) or even aluminum
Or make te clamping devices quite long to spread loads
If there are a few "common" fixtures, hard points could easily be let in and epoxied fast
hardpoints is no option, to much work
if this is the base of a CNC router, the router would do the work of the holes
Even a drilled hole with a hardwood dowel can hold a screw quite well.
MarkusBec is now known as MarkusBec_away
MarkusBec_away is now known as MarkusBec
Can anyone steer me towards a design for a 240+V 20Amp DC powersupply? Line voltage through a bridge rectifier, but I stumble over the capcitor size.
MarkusBec is now known as MarkusBec_away
can someoen tell me how to hook up my NO e-stop?
I have a big red switch, with normally open contacts
I want to run it to estop-in
use a safety relay. But usually it's NC contacts.
I'm using the NC contacts to keep the incoming A/C relay on
estop button isn't a power switch.
i remember when i was first learning to do machine setup
and my co-worker crashed the machine
over the noise i said, "shouldn't you hit e-stop"
to which he replied, "real men use reset"
NICK -r <al@smt>
pfred1 Can you shed light on a 250V 20A DC supply scheme?
calcite thats higher voltage than I've ever made a power supply to date
line voltage in , bridge rectifier and some caps... the caps are the question
OK me too ;-)
Are there two DC caps in every AC cap?
I get a little leary of voltages much past 36 thats when you enter the range of lethality
I don't know but i do know I've put DC caps back to back to deal with AC you filter on the DC side though so it isn't an isue really
True, but experience puts me in somewhere around 20K V ;-)
and 10s of KW ;-)
but never have I built a line voltage AC to DC converter
I got tossed about 3 feet once tinkering with an old tube amplifier all my amps since have been transistor based
oh I've built countless DC power supplies
but just never any that output such high voltage
I want to "supplement" the input to a VFD
if I were you I'd keep my eyes open for old microwave ovens for their transformers
they can put out like 1200 watts or so
No transformer needed at line input ;-)
and they're crazy voltage I've just fooled around with rewinding a few
so you're just going to rectify line voltage?
you should still use a transformer for isolation
SWPadnos my thoughts exactly
you never ever stick a rectifier directly across the line
An isolation xfrm sure
opps Too late !
well that's a transformer :)
I'm no expert, but everything I've seen related to safety says that
wall current is absolutely insane
you're talking momentary dead sorts of 50,000 amps or so on a 15 amp circuit before it trips
Hmm I have a small Baldor DC motor driver Adjustble output up to 180 V not an xfrmer to be seen
you can wire two transformers back to back
if their secondaries are the same
you know feed one primary hook one secondary to the other
but the input of a VFD is just an AC-DC converter, and they have no transformers!
calcite, it's possible to make "smart" supplies that use logic and controllers to rectify, basically the same way a switching supply works
yeah switchers have flybacks or whatever they're called i forget
Can you point me to a design SWP?
they're like flybacks
most VFDs will rectify directly, but they ground their chassis and have a +/- 170V bus (for a 220 input drive)
no, not really
I was going to point out the RMS peak boince of filtering
the bus goes much higher than the line in to allow for regen
I know there was a time a few years ago when places like Radio Shack started carrying "transformerless" wall warts
SWPadnos I was digging through my collection recently and ran across a few
A 20 amp unit must cover a lot of wall !
PC power supplies are easily 20 amps or better
you should probably use a cap that's about twice the voltage you expect to have
just at a lot less voltage
yeah, those smart wall warts are rarely more than an amp, and usually 300-500 mA
Trial and error to get acceptable ripple?
do you know what's acceptable?
there's a formula to figure out the cap you need
if you have a number, you can easily get the right capacitance value
well two actually depending on the voltage i believe it is
(a number for ripple)
opr is it current where you use one or the other I forget
Q=CV, dQ/dT = C dV/dT, since dQ/dT is current, I=C dV/dT
I know that when amp draw goes up, the Cap value must increase to output equal ripple.
SWPadnos that looks to me to be the simpler formula
a full bridge at 60 Hz has 120 peaks/sec
which is 8.33 mS (=dT)
so if you want X volts ripple, just plug in the values: C = I * 8.33 mS / (your acceptable voltage change)
C in farads, I in amps, dT in seconds (so 0.00833), and voltage change in volts
or you just throw the most capacitance you can get and hope for the best ;)
no, that's bad, if you have a transformer
and I think it's bad for the diodes as well
it causes the peak currents to be much higher
since it reduces the amount of time the diodes (and transformer) are conducting
we could use dV as 10 just to start
same amount of power output with less time for the charging spikes = higher current per spike
C =20A * 0.0083333 s / 10V
=16.666 millifarads, or 16666 microfarads
i'd have guessed 32,000
that's where Mariss gets his simplified formula, C (in uF) = 80000 * I
now why does the supply "base voltage not figure in these calculations? the 250V?
32000 would be correct for half wave
nah I'm a full waver
because you're using a formula that takes into account the actual voltage ripple, not the percentage ripple
I have a pile of those block bridges
if you wanted 5% ripple, the formula would have to incorporate the supply voltage
isn't half inherently more ripple?
I thought so I never half ass it
or it requires twice the capacitance to get the same ripple
so the same capcitance is required for a low of high volt supply, but high volt caps are physically smaller.
a high voltage cap will be bigger than a low voltage cap, if the capacitance is the same
it's more or less linear with respect to capacitor volume
high V caps are bigger to have more sufrace area to dissipate heat it seems
though at high frequencies you still encounter lots of internal heating
right I'm thinking AC caps....duh!
luckily you don't have to worry about that 60 cycles is clow
capacitance is proportional to internal surface area
area and distance
they can seem to make caps better today they keep on getting smaller and smaller
they have better pinhole removers ;-)
C = dielectric constant * (integral of area) / separation distance
yeah thats what i hear the dielectrics are just better today
C is proportional to area, and inversely proportional to distance
higher dielectric electrolytes
though I have been getting into reforming electolytics lately
lots of mine have been hanging around a really long time now
its a comfort to see them work before i use them in a circuit
caps are the weak link to longevity
not good ones that are used on a regular basis
I recently need two new ones in my oscope
electrolytics dry out over time, I don't think it matters much if they're in use or not
but if you let them sit they mess up
everything I have either did sit or does sit from time to time
I know Yaskawa lists cap replacement as a standard service item, I think at 5 year intervals
somebody ought to invent a spray or something
when I do reforming some don't come back
but its not many I'd say less than 10%
A quick look vinds some 6800mf 500V caps http://www.arselectronics.com/ARSWEB/CapPage2.html
they come in pairs! (for protection)
put some bleeders across thosep uppies!
they could bite!
I always wire my pilot lites right off the power caps so I can watch it bleed down
like that! neons?
its cool when you shut the supply down the pilot lite goes out slowly
at 500V it's going to be tuff finding grain-o-wheats
I just solve for LEDs at full voltage and slap the resistors in there
but so far to date the biggest I've ever done is 120V and at that I had ot use 5 watt resistors
I wonder what the bleed down to <50 V would be on 16K mf
I have a 31,000 mfd in my one supply I bleed off but it only goes to like 25V
and i never really hung around and timed it either
here I'll shut it off
I know the pilot on the VFD takes at least a full minute to go out.
And I have no clue what the bleed resistor value is.
its pretty faint now
and thats just at 25 VDC
or at least a full min.
the cap in there is pretty old I bet it isn't full capacity anymore
but thats always how I wire pilots across the filter caps to bleed them off
sort of a visual cue as to when its safe to monkey around
that and i like how it glows down
a parrallel resitor pair with the led on one leg could give light and any time one might choose.
sorry about the mistype
this isn't IRC on the Internut?
typos don't even bother me on CNN anymore
just throw it out there and hit spell check
get a load of how this guy saved all his packing materials maybe he thinks they'll have value someday? http://www.cnczone.com/forums/attachment.php?attachmentid=105409&d=1271557947
or he can reuse them when he fleabays all his parts?
the zone has a lot of builds for questionable hardware, but it's a great hobby, don't get me wrong
so's piling your money up and throwing a match on it I guess
really I think all overhead gantry machines are basically unsound mechanically
That would give very few people any pleasure at all. Money is the opposite of goods, anti wealth
calcite I take it you're not a power boater?
Boats should be quiet so as to enjoy the sound of moving wind and water
calcite in power boating you can burn a grand just going out and back in fuel alone!
A boat is a hole where you throw all your money
a hole in the water
I have a friend , last name Cost, his boat is named costly
does he slip it or transport it?
Oh it's a big boat, I don't know what goes over winter
ok he slips then
that can get costly
yeah they get drydocked in the winter usually
If he slips and breaks something...the Dr.bills could get miserable
usually a marina will all get together to rent a hoist for a day or however long it takes to haul
like a boat out of water...
A thing of beauty
my buddy Dave taught me all about boats enough to know i don't want one bigger than I can pick up by myself
I saw another build on teh zone where someone used 80/20 to the floor as framing material
is the stuff that cheap?
I like square stern canoes, Or a decked double end canoe
I might know it by another name
that extruded aluminum stuff lots use to make machines out of
you know with the tracks in it?
it doesn't look too cheap to me
Iron seems so appropriate for machinery
I'm partial to mild steel myself
in 1/2 inch or greater section
aluminum and steel are not internally damping, iron is
aluminum just seems unmanly
I was looking at the lathe build on a stone base, still only as good as the rail mounts
some irons I've worked with are a lot like mild steel
I don't like chilled very much
least i think all the really hard irons I've worked with are chilled of some sort or another
I have my mill up on mild steel now maybe that is why I get chatter sometimes?
least I think that I keep wanting to pour the base in concrete
Chatter might be flex in the head
yeah its an RF-32 round column
thing is so sensitive
I had an Wrong foo, used it for a bench drill
yeah its nice as a drill press
bit questionable when it comes to milling though
Made a lot of $ drilling holes with that
I have no complaints as far as its drilling ability goes
but i got a box of shattered endmills to attest to its sensitivity in that realm
since i switched lubricants its gotten a bit better
Cool tool, molyDee and Tapmatic for me until the stock runs dry, then I'll see
Oh, And Anchorlube
I found that chainsaw bar oil is just the thing on the ways
keeps them stuck together sort of
since i started using it its much better than it ever has been for me
it still operates smoothly but doesn't jump around so much as it used to
really I've switched to bar oil as my general shop oil lube for everything
hmm I just filled the saw today, And I use it to oil the underside of the rigs to slow down rust, I suppose a bit on the machines would be a good thing
I like it because its cheap and easy to get and sticks like crazy
I always have a quart lying around for my saw so ...
but strip down and slather up your wrong fo with it and you may like it
I paint it on with an acid brush
don't have the RF . and the mill has a pump, I'm sure a load of b&C would go through the pipes OK
pfred1 have you built any devices usint the LM2917/LM2907 frequency to voltage converter chip?
can't say that i have though I do have plans someday to try to use a current sensor of the national variety most likely
the LM2917/LM2907 sounds like some sort of a DA converter to me
I'm thinking of a tachometer forspindle speed
and you want to just hook a plain old meter movement to it?
if i was going to build atach I'd just leave it all digital from the get go
count the pulses and divide for time
then time slice that for an output
typically displays update twice a second
Well, the 3 1/2 carachter displays are Voltage driven and cost <$20
spell much ???
yeah I'm a 7447 kinda a guy I guess
and which display accepts the counts?
they probably make cheap digital tachs today
heck I had a rat shack one in an old car of mine
Yes, but they come in lousy packages and need light etc
Ohhh an automotive tachometer 12V!
but they divide by 5 6 and 8
4 6 and 8 rather
depending on how many cylinders you have
Audi 5cy can't use 'em
and display up to 10K Now I don't need that
and they round to 100
which isn't such a good thing
but someone must make cheap digital tachs for machines too
I was thinking a bicycle speedometer and calibrate the thing to read rpm
I'd imagine a meter with a frequency counter in it could be modified to serve your purpose
an pulse/time converter
the 7447 is a counter?
no its a display driver
you'd have to hook it up to counters though
well hook it to latches hooked to counters
so the 2907 is a converter, the dispalys in MP jones come with the driver built on
it'd be a very involved build there's easier ways of doing it
nite game over
MarkusBez is now known as MarkusBec
Tonok2_ is now known as Tonok2
hi, is somebody laser engraving with emc2
PCW_ is now known as PCW
yes there are some doing that I think
Looks like for now all the overtravel switches are going to be hooked in series..
ran out of inputs?
Tonok2_ is now known as Tonok2
izua_ is now known as izua
Tonok2_ is now known as Tonok2
[15:28:34] <skunkworks_> http://electronicsam.com/images/KandT/conversion/lastoftheblu.jpg
skunkworks_: What kind of PC chassis is that? I like it.. :-)
time to design a dust shoe
I *think it was a midwest micro case circa 1993 ;)
a bit hacked up
It works! Probably hard to beat the cost also .. ;-)
Do you buy your Opto stuff new or do you scrounge it off Ebay or .... ??? Seems like there area lot of sources for Opto type stuff these days ....
dust foot out of mdf or acrylic? vote now!
dust foot ?? what is that?
boxed up. shipping monday.
[15:45:16] <frallzor> http://qwindelzorf.com/router/images/dust_shoe.JPG
same thing, different name =)
Dave911: ebay - of course
frallzor.... acrylic would be difficult to staple stuff to... How about some good "low void" plywood?
How did we ever live without Ebay and digital cameras .... ??? As much as I hate the idea and monopoly of Ebay... I am addicted ....
Ebay fees are part of my monthly budget .. sort of like the electric bill, phone bill ...
world wide market
I have no problems with ebay. I don't know why most people have problems with it.
Dave911 no stapling is intended, that link just showed the concept =)
I sell a fair amount of stuff on Ebay and I have been ripped off on Ebay... and they could be much better ... their policies towards their sellers are getting a little stupid now... but it is pretty much a captive audience ....
If you get ripped off on Ebay as a buyer... and it is a criminal situation ... they will cooperate if they "have to". But they are pretty good at putting their head in the sand also..
Acrylic would probably look nicer ...
im thinking of trying alu
Sorry .. this is the emc irc right .. not the Ebay bitch/complaint dept ... just thinking about ebay some as I pass the 400 feedback mark .... as it has been an interesting journey ... ;-)
frallzor: Alum would be nice ... You are doing a Mechmate right?? Are you happy with the design of it?
its pretty much done
just need to fix the work area and dust management
I thought I saw some picts of it that you posted .. it looks really nice..
Does that machine use linear rails or angle iron edges etc?
angle iron ground to 90 degrees and v-bearings
Did you grind the edges?
the iron is places on 1 side and then ground
MarkusBec is now known as MarkusBec_away
so its a L with angles on the top
Did you just grind the edges "free hand" or did you use some type of jig??
let others do it by machine
tried first using the jig made for it, but it wasnt fun =)
OK... I saw that there are many methods of grinding the edges.... I always wondered if a grinding stone could be put into a table saw to make an easy jig ... I have everything to do that ... just haven't tried it yet ....
Tilt the arbor to 45 degrees and grind away ....
designing a dust shoe sucks
MarkusBec_away is now known as MarkusBec
Penmaker1 is now known as john_guenther
john_guenther is now known as penmaker1
recommended for people who like volcano photos: http://www.swisseduc.ch/stromboli/perm/iceland/eyafallajokull_20100416-en.html
are there lightnings in there?
volcanic ash causes frequent lightings
there can be several lightning strikes per second within the clouds
some of the pictures also give a sense of the scale, the plume is several kilometers wide, 5-10 is my best gestimate
Dallur1: you in iceland?
good morning gents
I live about 100km west of there
Dallur1: effecting you much?
skunkworks: not at all, the rest of europe has it worse than we do
that is good - well you know what I mean.
skunkworks, have you had a scope on an accupins device yet?
no - ended up tracing wires.. http://electronicsam.com/images/KandT/conversion/lastoftheblu.jpg
that is the last batch of signal wires. We have to trace all of those though.. shouldn't take too long
was there someone on here that had access to university publications?
wink wink nudge nudge
skunkworks: seb does
skunkworks: I can get some of the journals also
here's something from the latest CAD: http://dx.doi.org/10.1016/j.cad.2010.04.001
awallin_: thanks - this was unrelated to cnc... (wife is writing a paper for school and needed an article... I think she found an alternative)
hey I'm stupid i need help with the stepconf wizard
real men write inis and HAL by hand...
awallin_ yeah but my scale would probably have the same problem
awallin_ so apparently real men have more time to piss away than I do
what are you trying to do? can you pastebin where you think the problem is?
I'm trying to get the maximum velocity and the time it takes to traverse a distance to agree with one and another unless this hting doesn't run at maximum velocity
everything is OK at max velocity? i.e. G0 moves?
well it appears to take nearly twice as long as it should to me
dont forget acceleration time
I set the test travel to 4 inches and count almost 7 seconds at 1.5 in/s
I have my accel at 6 I can go higher
takes like a 1/4 second to accel
so like i said something that should take 3.5 seconds ot happen takes about 7 seconds or so
it is a slow computer though so maybe time moves slower to it?
Anybody know if the tripodkins module works with the z axis or just x+y?
awallin_: one of our hal files have 900 lines ;) impossible to write and maintain it by hand :D
micgesoh come on don't be such a big baby!
but seriously this time discrepency has been bugging me for days now
pfred1: can you HAL-scope the velocity of the axis?
awallin_ no because I have no idea what you're talking about
awallin_ i have oscilloscoped it
have you checked the scale values etc yet
awallin_ you know like with a real Tektronix scope
pfred1: ok. so does it look like it is accelerating smoothly to the set feedrate and then decelerating again?
and the step pulses look good to me just the test goes twice as long as it should
awallin_ well during accel and decel I can't lock the signal but it all sounds OK etc
it sort of scrolls during the accel and decel
we're talking an event that takes a 1/4 of a second I can't say as i can really take it all in
though i have seen it output bad clock when I adjust it and don't OK /cancel and restart
pfred1: and this is at a programmed feed-rate which is below maximum feedrate?
awallin_ I just use the little radio button in the pop up window I think its legit
check that the thread which stepgen is hooked to can actually produce steps as fast as you want
says now pulse rate at max speed: 24000 hz
awallin: yeah I saw this... Wanted to try one like this with z control as well.. math looks fun tho...
thats another oddity when I say my microstepping is some off the wall high number i can really get a nice pulse rate out of the machine
cliffb: it says it wokrs in XYZ in the wiki
but thats a nut I'll crack another time right now i just want what i should be able to do to all jive
awallin: I guess I'll read more carefully... thanks
awallin_ like if i say I'm running 32 step microstepping the motor flies!
in reality I'm only running 1/8th step
pfred1: ok... I haven't worked with stepconf much. The basic idea is to set BASE_PERIOD to something that your real-time hardware can handle, and then work with the max acc and vel in the ini file
awallin_ yeah I did that I went over it and had some difficulties so I dropped back to what the machine can really and is doing
and like I said I scoped the signal and its doing it no sweat
it can do 4X what emc thinks it can do even or allows me to do
unless i lie about the microstep mode
so I don't think its a step generation problem I'm having
but its still taking 7 seconds to do what it should do in 3.5 seconds and I just don't get it
so what is the max vel/acc in the ini file?
are you testing from emc/AXIS or from stepconf?
max vel is 1.5 in/s and accel is 6 in/s
right in stepperconf
I've had no problems setting accel to like 60 or so but the motor jumps around so I backed off a little
feed is probably programmed in in/min ?
yeah 10 TPI
I figured its a nice round number
I would suggest you test from emc2 where you can look at the ini file and program moves with g-code
I'll run 1/2-10 acme when I finish all of this up most likely anyways
awallin_ so what you're saying in effect is don't expect this to all work in stepperconf?
* frallzor needs to finnish dust collection so he can level the table
not sure. stepconf is relatively new, there might be issues
awallin_ i have seen a few bizarre behaviors in it
hence: "real men..."
awallin_ Ok thanks I'll just chalk it all up the the alphaware syndrome
its still a nice quick hack to get running with
awallin_ what made all of this even more confusing is the motor driver i have it hooked up to it wasn't immediately obvious to me what step sequencing I was running in
but I think I've worked all of that out now but the time still didn't agree so it sort of drove me a little batty
these new optocouplers i just got sure are nice TLP521s
[19:22:13] <elmo401> http://qurl.org/wy0
Is 750W Servo powerful enough for a Bridgeport conversion?
elmo401 I doubt it
you can anchor a boat with the steppers those things came with 1600 oz/in or something
they ran them in phase drive too didn't they?
elmo401 guy I knew got a CNC-1 for free for the taking
Anybody here know much about wire wound resistors and their inductance?
geo01005 I know they got it
but then again so does any wire
cliffb: the kins work for Z too
cliffb: my toy machine didn't have enough weight to allow for Z movement
and if it did, I doubt the motors could handle it
So I'm wondering, relatively, how much an increase of inductance would be expected by mounting a wire wound resistor with steel allthread down the middle of it.
geo01005 I think it depends on the frequency of the signal through it
which is why high freq inductors are air cored
alex_joni: thanks.. I've just started looking at the code. Did you write the module?
geo01005 has something to do with the permeability of the core or some nonsense
is there usaly a male or female db25 conector on the breakout boardS? :)
cliffb: yeah, a long time ago ;)
So from what I understand an iron core inductor would have thousands of times the inductance of an otherwise identical air core inductor.
geo01005 it varies with frequency
at some point iron can't keep up
I'm working with lower frequency signals, ~5khz
yeah you're no wheres near that point
its like at mHz where it happens
mHz or MHz ?
who was Mr. Mega?
who was Dr. Who?
Karl I'll do the dignity of capitalizing his initial but this mega clown I donno
pfred1: where is this cnc for the taking?
elmo401 oh he took it
elmo401 though the last i knew of him he'd still never done anything with it so maybe he'd give it away?
burnt out CNC-1s are worthless
except as scrap
Mr Mega worked down at the arc reactor, he made sure the work resistors and supervisor inductors kept doing their job
alex_joni: I'd like to try it with 6 motors for 4 axis of control. should be a challange... having your code to start should be a help.
So anyway... I have a 5 ohm resistor, the windings are 7 inches long, 40 turns of round wire, with a diameter of 1". The steel all thread is 1/4-20. The original inductance is 6 uH according to the manufacture.
Any guess at how much higher it is with the steel rod in it?
geo01005 I'm stil ltrying to figure out why you'd care
Trying to design a snubber.
don't those usually use those rings?
oh what the heck are they called?
elmo401 there's a name for the rings themselves but it escapes me at the moment
but you in effect make toroidal transformers on them
handy pkg mgmt for machines w/o internet http://keryxproject.org
i had to run the python version ( python keryx.py) because hardy doesnt have some pkgs
tom3p OK but it if works and there's no net connection what use is security updates anyways?
who said security? get what you want, leave the rest behind
tom3p I didn't know someone had to say what simply is
this still bugs me how this takes twice as long as it should
anybody know of a IRC channel that might be able to help me with my resistor/inductance problem ?
geo01005 #electronics ?
I guess they're just called ferrite toroids
cliffb: there is a version called a cable hexapod from NIST
[20:08:20] <alex_joni> http://en.wikipedia.org/wiki/Robocrane
I think the genhexkins we have in emc2 should work
are input in parport high all the time and needs to be dragged low, or are they low and needs to be dragged high ? :)
MrSunshine I think they're high Z until activated
so i should just GND the connector with my optocoupler then ? :)
oh i meant yeah to high Z
means they're nothing until they're enabled
i dont get it
high z is like a bus high impedance mode
what do you mean ?
im asking if i need to put 5V on them for them to register as "input" or something or GND them
so should i put +5V into the input pin or should i put GND?
no once they're enabled they'll swing how they're programmed they're not open collector
pfred1: I think he's asking about parport inputs
yes parport inputs
well yeah to make a 1 or high you have to put it in range
safest is to have a pullup to 5V
and drag them to 0 with an opto
alex_joni, so have them +5V until the opto is enabled that puts them to 0 then ?
but it depends for what you're using them
well switches and stuff
i put +5V in on the other side, and other in NC, when the NC side is connected to GND it will enable the opto
maybe need to be pulled low or something those also so they dont float :P
MrSunshine i haven't tried mine yet but I'm just going to go with a TTL output
it should work
well isnt +5V 0V TTL ? :P
still its the directions and high and low i dont know of the parports
direction varies with the mode in EPP
like which pins go what ways
thats just retarded =)
well just on the 8 data pins
[20:24:11] <MrSunshine> http://cuteminds.com/images/stories/Parport.PNG
im following that now
MrSunshine 2-9 you can make ins if you want to by changing mode
MrSunshine but in regular out mode just go wiht what it says
and as the drivers im using already has optoisolation i do not put optos on pin 2 - 9
rest of outputs are opto isolated, so are inputs
MrSunshine but how much current do your optos need?
MrSunshine parports can suck at sourcing or sinking much current and optos can be power pigs
on the drivers?
MrSunshine like how i have mine setup now I need to sink 16 ma to switch my opto
and there's no way I expect that kind of current out of a pport
so I threw a 74HCT245 buffer on it
make that AHCT rather
maybe not a bad idea =)
odly when its actually switching it only draws 6 ma but at rest it sucks back 16
go figure right?
MrSunshine this isn't perfect but its what i have on my pport: http://img11.imageshack.us/img11/1819/ppbb4sch.png
MrSunshine and I haven't really tested any of the input part at all yet
MrSunshine cept i have plugged it in and it doesn't seem to blow anything up in doing so
gaah why is everything "hex" not "quad" :P
245s are octos
and the output part does drive my motor drivers fine
even though as i have them setup like i said they're sucking back up to 16 ma
makes for some nice wave shapes ;)
MrSunshine even though my schematic says LS get AHCTs they're nicer
I just used a symbol that was in the program's library I didn't feel like making a new one
MrSunshine and i wouldn't really connect anything ot that last input with just the two inverterso n it I cheaped out and didn't feel like throwing another opto on the board :)
I don't think my Ball Nut fits my Ball Screw....
ewww.. that doesn't sound good..
they where bought as a pair>?
No. But they were bought from the same supplier with a note on the nut order that it should fit the screw previously supplied
I think that the screw has a 13.84mm root diameter, and I can't get a 13.75mm mandrel between the balls in the nut.
Jymmm: organic or server?
skunkworks: One of those that leave those spike balls everywhere and rip up concrete!
Anyway skunkworks, any luck with the Accupins?
skunkworks: I heard copper wire placed in the trunk will kill the bastard!
andypugh: no - spent most of the time this weekend hooking up wires... http://electronicsam.com/images/KandT/conversion/lastoftheblu.jpg
* skunkworks waits for jymmm to yell about panduct
* Jymmm is just waiting for it all to get hooked up then skunkworks to start cussing when he tries to troubleshoot. Then I'll be laughing my ass off!
skunkworks: and it's PANDUIT ;)
hmm, how much current can a relativly modern parport deliver? :/
cant find any specs
more then for "old" parports that could deliver 2.6mA
Don't ask a parport to source current, wire everything so that it switches by sinking current.
MrSunshine: It can't, use a driver like ULN2803
probably less for recent parports
1-2mA is what you should expect
or the 244,245
But the ULN2803 will convert that 1mA to 500mA sink. (with 7 or 8 channels on each chip, sharing the 500mA). That's enough to drive relays directly.
wow it takes 1.35 ma to switch a ULN2803
0.93 Typical, it says.
its still a pig and pretty dog slow too
takes like 6 microapms to switch an AHCT IC
they're dot matrix pin drivers aren't they?
least that was what they were developed to do back in the day
I'm a little concerned about the time shifting I'm getting with all of my buffer circuitry
The ULN can do 7MHz, that's more than enough for anything CNC-ish though, and they are cheap.
but it'll do it a us behind when its commanded to
they will be less apt to have issues with noise also.
I'm seeing a little undershoot on my signals coming out of the PC
Switching time in the datasheet I just closed was 130nS.
but so far it doesn't seem to affect anything so I'm not worried about it little ringing too but again minimal stuff
andypugh well they must be making better ones that Motorola is capable of
I was looking at a TI datasheet.
[21:43:29] <andypugh> http://docs-europe.origin.electrocomponents.com/webdocs/0881/0900766b8088183b.pdf
now there's an old rivalry
130nS low-to-high, 20nS high to low.
it sure has some mad fanout with 500 ma I'll give it that
I have just found that the ADC in my Arduino has a sample-and-hold. That makes life easier.
I doubt the device can out that on all outs at the same time though
but i don't feel like trying to figure out it's c/w rating
Possibly with cooling.
a 16 pin DIP package pushing 20 watts unlikely!
18 pin whatever it is
they put it in fine print i had a hard time finding it
[21:56:15] <frallzor> http://www.texasmicrocircuits.com/Documents/TMC-MP2-UG-V1_01.pdf
anyone know if this device has been used with emc2?
frallzor looks like nonsense for mach to me
frallzor it also really looks like something someone cobbled together in their basement
frallzor nice pendants usually have those 200 position rotary switches in them
maybe I cant fit an extra port for one? ;)
frallzor well they say its simple to use with mach
hey doesn't Sherline support EMC2?
like isn't EMC2 the default software for Sherline?
MarkusBec is now known as MarkusBec_away
does anyone here know why I am having a huge problem with my step pulses if I decrease "Step Time" below 5096?
MarkusBec_away is now known as MarkusBec
is it a common hardware limitation with PC parports or something?
by huge problem i mean the waveform changes from a balanced uniform square wave to a diminished high pulse wave
like the high part is about 5 us long followed by 40 or so us low
if i so much as go one step below this magic 5096 number
which wasn't so much an issue with another motor driver i made but this one is sensitive for hold time on the clock pulse
skunkworks I could draw a picture if it helps ;)
5096 is 5us... (it is in nanoseconds)
well the wave shape totally trashes below this 5096
the high gets really narrow while the low stretches out
its not what one would expect would happen thats for sure!
its not what does happen above it either
it looks plain wrong to me
I would guess that 5us is getting to the point of where the computer cannot do much smaller.
skunkworks Ok so its a hardware limitation of the PC then?
because let me tell you it has no problems making a lot smaller high shooting spikes
or should i say narrower
its just the wave becomes very unbalanced
one of my motor drivers will run on this ugly clock pulse this one won't though
and like i said it just sems plain wrong to me
although this is right at the threshold of my maximum step rate frequency this happend though I've also seen stepperconf say my max frequency was much higher than it is now too
oh well it may have something to do with that i just don't know enough about what affects what with any of this yet thanks
someone asked about "art to G-code the other evening, found this http://www.cnczone.com/forums/showthread.php?t=99063
With a gantry type table I see you use gantry kins to link the 2 axis. I assume you must set the home_sequence the same for both joints so they move together when not in world mode? What if a home switch is broken on one side? it's going to skew till something breaks is there a way around this? Like a limit I can place on error between 2 joints... anyone done this?
it was me calcite
but I know what I Want :)
and nothing comes close to it
Well, It's a led
Aspire or bust is my new motto
I ask for so little, and boy, do I get it! ;-)
Did you look at Tux Plot? I could not get it to work with EMC qualified Ubuntu
cliffb: Good question
Cliffb Put a hard stop in , stall the motors if the limit fails.
You should be able to look at the joint positions in HALscope and check that they are "live" during homing. (I am not sure, but I think they are) and then it would be just a case of a bit of HAL magic to set an e-stop if the difference between the two gets too huge.
Ok.. I like idea a little better.. I guess I'll wire motor overcurrent into the e-stop as well.
Although, I suspect that you would have to be a bit clever not to have it always e-stop when one side homed and the other hadn't
You could just have some extra unsubtle limit switches that disconnect power when hit by the gantry.