[vakeiros]

hmmmm so if i get for exemple a 48V PSU (which is about the max these drivers can take... i think) it would be better right?

it's a possible future upgrade i think...

thanks

[aarggh]

hmmmm so if i get for exemple a 48V PSU (which is about the max these drivers can take... i think) it would be better right?

it's a possible future upgrade i think...

thanks

Correct.

Another thing to consider when selecting PSU's is that Mariss from Gecko did some testing of PSU's, that really only pretty much confirmed what I think we all knew anyway, and the general vibe was that the really cheap Chinese PSU's were fairly suss as to the reliability and the ratings. For example, on a 3 stepper machine you'd reasonably safely spec the PSU Amp rating, at roughly 60-70% of the total combined max draw of the steppers. The reason it's not 100% of combined, is that you would never really have all three steppers running at max draw simultaneously. So let's say that calc gives you a target of 6A required, so you buy a PSU rated at 7A, gives you 1A head room right? Maybe not, as from many I've seen myself, the supplied specs can be wildly optimistic and only under ideal conditions. Or not sustained for long periods. For every degree above ambient you would need to derate the PSU output for example. There may also be significant noise on the output, thus lowering headroom.

While it's not something you need to worry about terribly, what this means is that you need to just factor in some allowance as not all PSU's are equal.

If you can find them on Ebay, old Telco or network/switching PSU's are generally 48VDC and are absolutely gold, as they are rated very high output, they have a high efficiency rating, and the output is generally filtered extremely well and will sustain a very high continuous drain while being made to last a very long time. Other good ones are also used in conjunction with battery backed up solar arrays. I have seen Eaton APR48 PSU's on Ebay for $100 or so previously, these supplies are worth in excess of $600-$800 or so new!

cheers, Ian

[vakeiros]

well i've been out of town so only today had an oportunity to make a few tests on my pc/cnc
i've checked the output signals of my "less old" pc and everything looked good so i put the "older" pc back together and BAM cnc works properly on that so i deducted that the problem is low amperage on the newer boards i think i'm gonna buy a parallel port buffer like this just to lay arround in case of something happen to the older PC but first i'm gonna wait because the kit come with a different breakout board (i think) and i'll try this breakout board on the less older PC to see if it works good. however i'll keep the old p4 1.6ghz dedicated to the cnc this way i can always be doing something else on the other PC without disturbing the CNC work.


i've the new motors on the way now (both steppers and spindle) and a new doubt came up.
on my ctual steppers i've the Mach3 values for them on the CNC manual, what about the new ones how do i find the values?

thanks to all and regards

[vakeiros]

hi guys,

sorry to bother you again but i kind of need your wisdom XD

My stepper kit arrived (3x270Oz + 3x 542 drivers + 10A 36V PSU + Breakout board).

well i've tried the breakout + 1 driver + 1 stepper just to see if i could make this thing move and success!

i'd to do a complete new CNC Controller Box because the original it's too damn small to all the new stuff :P

this has been an amazing learning experience for me, now i can understand how this stuff works... i even found uot why i was having troubles with the newer PC, it happens the original breakout board only uses power from the parallel port and none of the signals it's photocoupled, the photocouplers are on the motor drivers (strange thing i know but the original pcbs are very $hitty) and as there are not enough Outputs they wired 2 driver enablers to the same port, and these were exactly the steppers i was having troubles, i didn't try but i'm almost sure if i disconnect one of these drivers i think it would worked flawlessly, whatever... the new board has all the I/O ports photocouled and needs +5V PSU so all the power for signalling the drivers will go from the 5v psu so no more problems with the PC... i think :P

now my doubts:
1- what settings should i use on the DIP switch on the drivers? as the steppers are 3A i kept the switch on the 3A RMS position (or should i lower it?).
2- What about the stepping config??? i really don't know what setting should i select here...
3- what settings should i use on the Mach3 motor settings? (acceleration, velocity, steps per rev [here i think i must insert the same value that i selected on the driver])
4- now that i'm building a completely new control box and i'm improving the CNC i decided to include limiting switches on the XYZ axis, i know how to set them up (each Axis will have 2 microswitches in series and connected to an input of the breakboard) no questions here. But what about MACH3 configurations? i know i've to assign the input pins but i don't know which parameters, i mean, for example i'll have the limiting X switch on pin 15, i'll go to Mach3 configs, on inputs i don't know where to select the pin 15..

i think that's all....

do you want to know the best one?
guess what's my original PSU? keep in mind that the original set up has 3* 2.4A Vexta steppers + 1* 1.55A Vexta stepping... BTW: what does it mean the amperage of the motor? it's 2.4A per phase or 2.4A total? , anyway my original PSU it's a 24V 4.16A... man this is too damn little for 1 or 2 motors!! they put these for 4 motors???? damn chinese guys XD... i know i know, low price, low quality

thanks for everything and sorry all the questions.

regards

[vakeiros]

hi guys, i really need some help...

[handlewanker]

Hi, I'm still new at this lark, but I've built a few electronic gadget so my 2 cents worth.....as far as power supplies go, if you exceed the amperage delivery the voltage will drop......that works for transformer/rectifier/capacitor power supplies......the bigger the trannie the more amps it puts out.

When you get to switch mode power supplies, if you exceed the amperage you get blue smoke from the output regulators......BTDT.
Ian.

[vakeiros]

well i've figured out the settings for motor tuning, about the limitting i'll have to do some trial and error tests but i'll figure it out eventually now my only real question it's about the Driver output current, motors are 3A per coil, so i don't really know if i have to set the drivers for 3A RMS or 3A peak... can anyone help me on that?

regards

[aarggh]

well i've figured out the settings for motor tuning, about the limitting i'll have to do some trial and error tests but i'll figure it out eventually now my only real question it's about the Driver output current, motors are 3A per coil, so i don't really know if i have to set the drivers for 3A RMS or 3A peak... can anyone help me on that?

regards

Sorry I haven't had much time on the zone lately, what version 542 do you have? I'm guessing DQ542?

I don't recall if my drivers have the two current options, so in your case the 3A RMS sounds the likely setting but I'll confirm what mine look like tonight and report back. If yours have the half current setting you'd most likely want to enable that as well to reduce the current and heat.

cheers, Ian

[vakeiros]

mine are DQ5423MA they have a bunch of settings. i think they have half current that is enabled. what about the microstep setting? i still don't know what should i select here...

thanks

regards