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 Affordable Mark Roberts Pan Tilt Head? 
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Post Affordable Mark Roberts Pan Tilt Head?
Is it me or is MrMOCO new Robo Head http://www.mrmoco.com/heads-dslr/products/robo-head/ Just a Merlin Sky Watcherhttp://www.scopesnskies.com/prod ... letop.html with a New 3d printed side panel. ?
[flickr] Imagerobo-head-1 by D 1, on Flickr[/flickr]
[flickr]Imageskywatcher_merlin_aynscan-az_goto_goto_mount by D 1, on Flickr[/flickr]
I think it is ! So thats £3500 for a £200 PT head :D :D :D :D
D1


Sun Feb 14, 2016 9:36 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Wow. You'd have to wonder ?

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Sun Feb 14, 2016 2:05 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Where is the matt black spray can - lol

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Mon Feb 15, 2016 2:39 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
So we are all of the opinion that it is sky watcher . Their must have been some very expensive modefictions going on inside . Lets face it a can of black paint costs £6 = modifications £3294?
D1


Mon Feb 15, 2016 3:42 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
It does have repeatable moves etc. Clearly its the same case though.

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Mon Feb 15, 2016 6:47 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Quote:
LOW-COST high-end, quality, pan tilt head.


I am currently working on offering a pan-tilt-head for ~450-550 €. If 4.500 € are "low-cost", then how should I call my pan-tilt? :lol:

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Sat Feb 20, 2016 1:07 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
BlueGene wrote:
Quote:
LOW-COST high-end, quality, pan tilt head.


I am currently working on offering a pan-tilt-head for ~450-550 €. If 4.500 € are "low-cost", then how should I call my pan-tilt? :lol:



Ah me to already up to £400 in parts alone so you are doing better than me . Look forward to seeing it .
D1


Sun Feb 21, 2016 10:08 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Currently checking out different worm gears:

https://www.youtube.com/watch?v=tYD4glVkDlU
https://www.youtube.com/watch?v=-VeqEGIPiJM

Owning a 3D-printer has its benefits ;)

Some standard stepper motor, bearings, worm gear (wheel will also be printed) and Arca Swiss mounting plates and you can build a real "low-cost" pan-tilt, which has no backlash, enough torque and is lightweight.

The control box can be purchased separately, starting at 230 € as an assembly kit.

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Sun Feb 21, 2016 11:11 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Yes 3d printers have their uses . I have one just dont use it much .
Think we are on with different beast which is good . Their are many ways to solve a problem and the requirements can be radically different . Basically i have the task of building a bullet proof PT head. My old one was quite well built but theirs always room for improvement. New one is mainly constructed out of 15mm ali plate and uses steel belted timing belts . You can see why the materials bill is mounting up but you pay for what you get .But its built for studio use so lightness compactness as gone out of window on this one :D
D1


Sun Feb 21, 2016 1:45 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
D1,
And there was me thinking your 'old one' was the gold standard we were all trying to emulate.


Mon Feb 22, 2016 7:07 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Kitwn wrote:
D1,
And there was me thinking your 'old one' was the gold standard we were all trying to emulate.


Its all same gearing just bulked up a bit . Theirs some great gear been made out their think Edward and Gerald get the gold standard its those harmonic drives they use .

D1


Tue Feb 23, 2016 1:41 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
DISPLACEMENT 1 wrote:
Yes 3d printers have their uses . I have one just dont use it much .
Think we are on with different beast which is good . Their are many ways to solve a problem and the requirements can be radically different . Basically i have the task of building a bullet proof PT head. My old one was quite well built but theirs always room for improvement. New one is mainly constructed out of 15mm ali plate and uses steel belted timing belts . You can see why the materials bill is mounting up but you pay for what you get .But its built for studio use so lightness compactness as gone out of window on this one :D
D1


Is that what your new control box will be used with ?

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Tue Feb 23, 2016 1:48 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Got a nice job somebody wants a full rig :D We have a lot of old rostrum camera gear that can be modified . Guess what bit this is going to be
[flickr]Image2016-02-22 11.32.47 by D 1, on Flickr[/flickr]
[flickr]Image2016-02-22 11.32.58 by D 1, on Flickr[/flickr]
Just ordered a DMC16 so that will be interesting will let you know how it goes and how much it cost to get to UK :(
D1


Tue Feb 23, 2016 2:05 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Holy Plumbicons, Batman!


Tue Feb 23, 2016 4:59 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Look out Bot and Dolly ;) A serious bit of kit in the making. Good to see the work is still flowing your way.

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Wed Feb 24, 2016 11:22 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi Mike yep going to be biggest rig i have built so far and its got to run real time . So bit of a journey into the unknown but got quite a while to do it so should learn a lot .
First thing i have learnt is really disappointed with those Leadshine DM432c http://www.leadshine.com/UploadFile/Down/DM432Cm.pdf straight out of box they are pretty crap . I am hoping tuning them with the software improves the situation but just using DIP switches hasn't achieved much . They are quite and smooth but they stall out well before any other driver i have . Dont think i can use them on the new rig which is a shame .
Also realized my old desire to stay at 12 volts so i could use it in the field was a bit misguided . Up to 36v at mo and 48v would be prob be better you get so much more speed :D .
D1


Wed Feb 24, 2016 1:02 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Interesting you are dissing the Leadshines. What are you comparing them with?

In my experience they do not stall any easier than other drives operating at the same current and voltage. In fact, since the motor runs cooler you can often set the current a little higher than motor spec if you need... also watch out for the way current is specified - sometimes it is RMS and other times Peak, so you may be comparing apples with oranges, even when you think the current is the same...

In any case, given speed is an issue, perhaps you should be using the DM856 which is designed for higher current and higher voltage? G


Wed Feb 24, 2016 4:06 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi Gerald i have i Little bench set up which i have been plugging in different drivers and motors into . Not very scientific i know but it is good for getting a overview . I even leave the motors on all day to see if their are any heat issues . As you may have guessed the rig is for stop frame so i want it sit powered up for hours without any issues.
I have two drivers plus the laedshine at the moment and one more turned up yesterday . http://cnc4you.co.uk/resources/CW5045.pdf http://www.schmalzhaus.com/BigEasyDriver/
This is the one that turned up yesterday https://www.cnc4you.co.uk/Microstepping ... olt-CWD556 Which i think i will be going with if it test ok . The company is very good and helpful which means a lot to me . All the drivers and motors on my mill were supplied by them
As for current i set it to what i believed to be correct then i bracketed to either side to see if their was any improvement . I even have a ammeter wired in to see how much current the motor driver combination is pulling .
Maybe the software tuning will help but this is a issue to because some of the drivers will have different motors plugged in for different applications. I was hoping just to flip the DIP switches if the current was different not to have to reprogram the driver every time.
As for voltage i think i will stick at 36 volt if the rig was for me i think i would go higher as you say but their are health and safety issues as you may have guessed i am not a trained electrician .
D1


Thu Feb 25, 2016 1:45 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi Gerald had time to test the new driver today against the Leadshines as i say not very scientific but theses are the results if they make any sense to you

STEPPER MOTOR DRIVER SETTINGS
CDW556

NEMA 23
2 .1Amp 36 volt

800 steps per rev micro stepping max pulse per sec 12000 dragon
1600 steps per rev micro stepping max pulse per sec 20000 +dragon

NEMA 17 48mm
1.5 Amp 36 volt

800 steps per rev micro stepping max pulse per sec 19000 dragon
1600 steps per rev micro stepping max pulse per sec 20000+ dragon

LEADSHINE DM432C

NEMA 23
2.05 Amp 36 volt
800 steps per rev micro stepping max pulse per sec 2000 dragon
1600 steps per rev micro stepping max pulse per sec 5000 dragon
3200 steps per rev micro stepping max pulse per sec 11000 dragon


NEMA 17 48mm
1.39 Amp 36 volt
800 steps per rev micro stepping max pulse per sec 10000 dragon
1600 steps per rev micro stepping max pulse per sec 20000+ dragon
3200 steps per rev micro stepping max pulse per sec 20000+ dragon

The max pulse per sec is the amount the motors run at before it stalls out

It almost seems as the Leadshine cant deliver enough current as i say i haven't software tuned them yet . But thats a no go for this job so think it may have to be the CWD 556 . The other advantage of these drivers is i can get them next day . So if one fails i wont be holding up production waiting for one to arrive from China . A simple practicality I am afraid.

A few pics of test set up and the range of motors i am using . These all work fine with CWD556 I am prob doing something stupid with the Leadshines but i cant figure it out :(
[flickr]Image2016-02-25 14.42.37 by D 1, on Flickr[/flickr]
[flickr]Image2016-02-25 14.42.06 by D 1, on Flickr[/flickr]
D1


Thu Feb 25, 2016 7:03 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi, Di, not at home cannot check my figures properly, I have leadshine DM442 drivers running NEMA 17's rated 1.6A peak? Voltage is set to 29dc and found dropping the current to between 1.0 A and 0.6A they ran cold and much smoother than at 1.6 with much better torque characteristics.
Then tuned the driver with software with better results again. I read and re-read the Leadshine instruction, did an Auto tune then my own thing as their default settings for resonance did nothing for me. I set values from min to max until I a got reasonable response from the motor then gradually increased / decreased the setting by small amounts for all three resonance settings.

Edit: DM442 (200Khz) was DM422 (75Khz)

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Thu Feb 25, 2016 10:08 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi Mike hope ya hols going well sun here but really cold . From my test the problem is more acute with the Nema 23 s . But even so the difference in torque between the two drivers is considerable . Got me stumped were did you get your cable from for tuning the leadshines i will see if that improves things .
D1


Thu Feb 25, 2016 11:28 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Stupid question for someone like you D1, but have you got the Standstill Current Off which halves the current after a period of no movement ?

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Thu Feb 25, 2016 2:49 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hey D1,
I had some issues when I first transitioned from the BEDs to the Leadshines. I recall the auto tune is something you need to do every time you change the motor. Also, now that I have had them for awhile they do run they way they should, quiet, cool and powerful. And as Gerald mentioned I do push more power at them. I am running 24v psu 14.6 amps and all the motors are running smooth. A side note, the last time I played around with DF using my BEDs running under Mantis I noticed that I was pushing the motor I had attached way up at 20,000 steps and it seemed to run very slowly. The BEDs were always left at the default micro step but things did not work the way the had before. Not sure what happened there. Also, those Arduinos will never push the motors as fast as the DMC16 or Mantis will. Maybe when you get the DMC16 things will be different.


Thu Feb 25, 2016 5:25 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
amongstmyselves wrote:
Stupid question for someone like you D1, but have you got the Standstill Current Off which halves the current after a period of no movement ?


Hello its my understanding that the half current only operates after the motor as stopped for a second or two . Which is good it stops the motor getting hot when its not doing anything and thats the way i have the CDW556 set . So it should have no effect when the motor is running i could be wrong about this though but in any case i have tried it in both positions .

Hi Doug i remembered you had a few issues glad you got them sorted now . I am aware the Dragon Arduino combination as a max pulse limit of 20000 pulse per sec thats why i turned down the microstepping in some case so i could get the motor to stall out .
Mike seems to be starving the motors of current and you seem to be giving them a bit more assuming by power you mean current but you are both getting good results getting really confused now .
I will keep fiddling as i have five of these drivers so they need to be used on something.
Cheers D1


Fri Feb 26, 2016 12:58 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
DISPLACEMENT 1 wrote:
Hi Mike hope ya hols going well sun here but really cold . From my test the problem is more acute with the Nema 23 s . But even so the difference in torque between the two drivers is considerable . Got me stumped were did you get your cable from for tuning the leadshines i will see if that improves things .
D1


Zapp Automation, make sure you get the right one that is matched for your driver. it cloudy at present but warm and sun will be along soon ;)

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Fri Feb 26, 2016 1:09 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Cheers Mike will order one then i might be able to sort this out
D1


Fri Feb 26, 2016 1:20 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hmm i ordered the big easy driver and its little brother for myself last week as well. wanted to move away from a stepper motor shield that ties up some of the pins that other shields want to use. i have done a little extra research that indicates if you want faster stepping the 32 arduino due running at 84 MHz or chipkit 32 running at 80 MHz aught to give you a little more headroom.


Fri Feb 26, 2016 11:31 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
chardie wrote:
Hmm i ordered the big easy driver and its little brother for myself last week as well. wanted to move away from a stepper motor shield that ties up some of the pins that other shields want to use. i have done a little extra research that indicates if you want faster stepping the 32 arduino due running at 84 MHz or chipkit 32 running at 80 MHz aught to give you a little more headroom.


Dragonframe tops out at at 20000 pulses anyways so changing the arduino wont make any difference . The issue is the difference between the Leadshine and the other drivers i have which are operating under exactly the same test bench settings . I have ordered a lead for the Leadshine so we will see if i can getting running better .
D1


Sat Feb 27, 2016 1:44 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi, D1, you might find some interesting reading here if you have not already checked it out: http://www.geckodrive.com/support/step-motor-basics.html

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Sat Feb 27, 2016 1:58 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi Mike that was a interesting read good find again . It shows how many things effect a stepper motor basically you cant rob Peter to pay Paul . Theirs a sweet spot you have to hit for your application . Not been great a maths i tend to bench test things rather than working things out on paper .So a monitoring heat, stall speed and torque ( well gripping the motor shaft with me fingers ) gives me a rough idea whats going on.
I just cant get this to work on the Leadshines and yet the CWD556 are working as they should be. Heat is not a issue specially in half power mode at rest and torque and speed is fine for application. Think they prob could run smoother but that isn't much of a issue . Theirs quite a bit of gearing in the rig which tends to smooth things out a bit and real time is only for building the move . The actual shot will be stop frame. Precision wise dont think theirs a issue i have been using motor and drive combination on my mill years now and it doesn't seem to drop steps.
Hopefully the cable will turn up next week and i will give the leadshines another go but for the mo they are going back in their boxes :(
D1


Sat Feb 27, 2016 2:53 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Forget the maths, the table at the bottom of this article give a good indicator why too much micro stepping is a compromise when you need torque. I run my Leadshines at 10 now instead of 16. With 600:1 gearing the micro stepping only serves to give smooth motion.
http://machinedesign.com/archive/microstepping-myths

If you Google "microstepping vs torque" you will find lots of articles for bedtime reading ;)

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Sat Feb 27, 2016 11:53 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Cheers again Mike i dont seem to have a problem with torque or speed when running the CDW556 . I haven't noticed much difference between settings with my simple trying to stall the motor with my fingers test . I usually run at 16 just because that was the Max of the BEDs might go up to 32 with the new drivers .
I cant believe you only get 4.91% of full torque at 32 micro stepping surely i would notice that with my finger test ?
But its not a issue anyways and i am going to avoided extreme micro stepping because Dragon in its standard form wont be able to put out enough pulses a sec to drive it .
Found this http://www.ehow.com/how_10033323_determ ... otors.html me and me maths was struggling . But if ya want to work out your final rpm from the amount of pulses this is how ya do it :D .
D1


Sat Feb 27, 2016 12:39 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi D1. Based on your results you do seem to get a bit more power from the 556 at higher rpm. This may be due to a motor mismatch or some other random effect of the smoothing algorithm. (BTW - the 556 looks like a clone of a Leadshine M550 - seems the Chinese are even copying each-other's drives...)

But I think if you are not needing high rpm for the rig, the difference between the drives at low to mid speed isn't significant - so either drive may suffice? (though you'd be better off testing with the motors doing what they are intended to do, rather than free-wheeling.)

Since you have limited pulse frequency - 1600 microsteps seems a good compromise. At 20k pulses/sec the max speed will be 750 rpm - not stellar but useful.

Re the Leadshine fine tuning - I would ignore it. It won't change your life - I mainly use the software when I need to set lower current than is available from the dip switches. G


Sun Feb 28, 2016 3:24 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi Gerald thanks for input . CNV4YOU assure me the CDW556 is their own design , they do like to chat on the phone. But as you say their are so many drivers out their who knows whats what .
I think i can use the Leadshines in my box just for the pan tilt and focus controllers . They are smooth and the torque / speed is sufficient for the head .
For the new rig i will go the CDW556 route they do seem to to do the job . I have nearly finished the new head and gearing for revolve so will test these with load before i commit to buying another 7 556s .
Next issue is power with a meter the range of motors pull from 1.5 amp to about 3.5 amp if you really put a load on the motor . The highest amp 36 volt power supply i can get is 11 amp . So this means i need two which is a bit of a pain their quite big . Had a look at server power supplies you can pick these up really cheap . I imagine they are of quite high spec considering their end use . In fact they may be to good, to many protection circuits built in . Think i read somewhere unregulated power supplies are best for motor drives but i could be wrong .

On refelction for the custumers rig it may not be best to be hacking things . But i may get on to play with they are really cheap :D
D1

Ps they not making the VOLO anymore so not many crane options out their


Mon Feb 29, 2016 2:19 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
CWD556 assure you? Perhaps there was some other reason they also happened to design the box and connections to mimic the Leadshine? :) It's not just them, but Longs motor, Kelingc etc. It's hard to tell what you are buying sometimes. Some may even be better than the original, but who knows...

Simple transformer supplies are best if you aren't concerned about weight - they are very reliable and don't need noisy cooling fans... as a rule of thumb add up the current of all the motors and divide by half. A 500watt xformer should handle a small crane rig quite easily - and at animation rates it will be cruising... just make sure the unregulated supply voltage is not above the drive specs. Some xformer supplies will have a higher unloaded voltage than their rating... G


Mon Feb 29, 2016 4:09 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Will look a bit more into the transformer thing . Quite enjoying this job learning a lot lets hope the it all works out . The DMC 16 turns up this week i think .
Sorry Gerald i did consider Mantis but i am dealing with animators and they are happy with Dragonframe as a package . The real time element is just for shot creation . Maybe next time when somebody is after proper real time .
Got a rack and pinion to deal with next . Think a belt would have done but the rack is from the bit box of the old rostrum so may as well use it . :D
[flickr]Image2016-02-29 12.11.56 by D 1, on Flickr[/flickr]
D1


Mon Feb 29, 2016 4:39 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Hi, Di, the Gecodrive link gives useful info on power supply types / current requirements, maths is "easy" ;)

Gerald, The Leadshine DM442 I use with a 17NEMA 26:1 Phidgets gave velocity reading of 20 max before stalling, tuning gives me either 50+ or 70 not sure until I am home also dropped the Max current to between 0.6 and 1.0A - rated at 1.6A peak. I seemed worthwhile in my case to Auto tune then set up the three bands. With the other stepper motors 17NEMA 400 step units I just Auto tuned to give good results.

Edit: DM442 (200Khz) was DM422 (75Khz).

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Mon Feb 29, 2016 6:21 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
Well, I've almost completely given up on steppers because of their inherent noise. Servos are smoother and far quieter. I think even Gerald, who I think used to have a love/hate relationship with servo motors, seems to have begun to tentatively love them again:) (Only kidding, Gerald) Unfortunately they are bloody expensive, but maybe justified for professional use.

The only time I use steppers is when I don't need massive speeds, for example with a focus motor and small gear reduction, say 5:1. Then I use the SlilentStepStick drives on the silent mode and they are very good indeed. Otherwise it's servos all the way for me.

BTW, I have finally finished my robotised studio stand with dolly track et all and tomorrow I will be using on a big stills shoot lasting a week, so we'll see how I get on with the pressures of a real job.

D1 and others will be interested to know that I used two Hewin type 15mm steel tracks for the column with bearing blocks. Unfortunately I can "feel" the tiny bearings as they move, which then transfer tiny vibration to the arm. Not sure if this will show on video filming, as I haven't rigged it for video yet.

Because I am rather paranoid about vibrations (about everything) I will be converting the column to wheel bearings after my shoot. Wheel bearings also offer very small resistance, unlike bearing blocks.

I have the polycarbonate wheel bearings for the dolly tracking and they work very well, very smooth. I have three "blocks" with three pairs of small wheels each.

Edward

Edward


Mon Feb 29, 2016 9:30 am
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Post Re: Affordable Mark Roberts Pan Tilt Head?
In defence of the Mark Roberts head, I have read the specs, and it is equipped with servo motors with encoders, etc. This is where most of the money goes. The rest is just a carcass, well, kind of. Anybody can make a cheap pan/tilt. It's what's inside that counts, plus the software, of course.

Edward


Mon Feb 29, 2016 9:37 am
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Joined: Mon Nov 22, 2010 1:18 pm
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Post Re: Affordable Mark Roberts Pan Tilt Head?
edward wrote:
In defence of the Mark Roberts head, I have read the specs, and it is equipped with servo motors with encoders, etc. This is where most of the money goes. The rest is just a carcass, well, kind of. Anybody can make a cheap pan/tilt. It's what's inside that counts, plus the software, of course.

Edward


Ah the full Flair software is extra another £5000 i believe :D You would think if they are going to all that trouble you would build your own mechanics . They obviously have their own in house CNC enginering department . I have had one of those telescopes heads too bits.Its ok but really not great and def not up to your standards .
I agree about servos if ya want to go fast they prob best bet and all the pro gear i have come across goes that route . More expensive CNC routers tend to have servos to . But in the wonderful world of animation think steppers are fine .
Hope ya shoot goes well that will highlight any probs / good luck :D
D1


Mon Feb 29, 2016 10:16 am
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