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motor madness
« on: October 07, 2009, 05:34:16 AM »
hello friendly mach people ;D

I have recently purchased components for a cnc machine I intend to build and I'm
already running into some real problems, hoping someone might be able to help me.

Components:

GWR Elektronic SM44PCV5.1 driver board
(http://shop.strato.de/epages/61125483.sf/de_DE/?ObjectPath=/Shops/61125483/Products/%22SM44PCV5.1/RK2%22)

GWR Elektronic SMN 4515V1 power supply
(http://shop.strato.de/epages/61125483.sf/de_DE/?ObjectPath=/Shops/61125483/Products/SMN4515V1)

M5776/2.0/1.9 2 Phase High-Torque stepper motor 2,0A
(http://shop.strato.de/epages/61125483.sf/de_DE/?ObjectPath=/Shops/61125483/Products/"M5776/2.0/1.9")

I would much have preferred a geckodrive of some sort for this project but being in the colder end of Europe the shipping and taxes and toll added up to be about the price for a geckodrive 540. I now regret cutting costs in this particular area :(

Setup 1 is a  2,8Ghz ibm thinkcentre PC with xp SP2 running mach3 and nothing else. On board and off board gfx cards. Mach3 drivertest reports excellent.

Setup 2 is a 1.6Ghz noname (asrock mobo)  PC with xp SP2 running mach3 and nothing else. On board and off board gfx cards. Mach3 drivertest reports excellent.

Setup 3 is a 500Mhz noname (msi mobo) PC with xp SP2 running mach3 and nothing else. Off board gfx card only. Mach3 drivertest reports excellent.

The motors are noname (literally) motors, 8 wires, 2 phase, 2,0A bipolar serial, parallel 4A, coil voltage 4V, coil resistance 2,0 Ohm, coil inductance 6,4mH. 200 steps/rev with 1.9nM holding torque. Wires are red – blue – green – black – red/white – blue/white – green/white – black/white.
Wired as bipolar serial:

blue and red/white connected and isolated
green and black/white connected and isolated
A - blue/white
B – red
C - green/white
D – black

Above motor information supplied by seller.

The SM44PCV5.1 driver board is configured at 1.5A and hooked up to
a 36V supply.

Test procedure:
I start everything up, enter mach3, set up ports and pins for just 1 stepper to test this out. Board has led's to indicate ready status, hitting e-stop on the board registers in mach 3, all is well.

Now come the problems. I've made a small test axis, 300mm in length with a motor attached to one end via a flex coupling. The drive screw is a 12mm, 60 degree thread, 1.75mm pitch. A preloaded nut is attached. Action is smooth and the nut spins easily. The board is set to half-step. Motor tuning is initially set as follows: 200*2/1,75 = 228,57 steps/mm. Velocity 100mm/min. acceleration 4.

This does work, the stepper moves, but nowhere near 100mm/min. Fiddling around with the numbers the very best I have been able to achieve is less than 1 rev/s. Any higher and the stepper loses all control of itself, losing steps (often every step), moving backwards, sounding like a hammer drill... it isn't good. And even at very low speeds where it does work it runs faster in one direction than in the opposite. I tried increasing the kernel speed in desperation and that does actually work, makes it run smoother but not a lot faster. Worked best at 100khz, which I understand from the mach3 setup video tutorial to be way excessive.

Hooking up another stepper, same type as the first, things get even weirder. The settings for the first axis I copy to this new axis. This motor behaves as screwy as the first one, but not in the same manner, jerks are different and what will make the first axis slow but smooth makes the second jerky in 1 direction and not working in the other. I have tested with a few older steppers salvaged from various places, all were 6 wire types. Behaviour persists regardless.

I'm really at my wits end here I just can't figure this out. Doesn't help that I'm rather new at this - almost all I know, I've read, so practical experience is not abundant. If anyone has any insight, any at all, or has maybe worked with this particular board before please help me.

Offline Hood

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Re: motor madness
« Reply #1 on: October 07, 2009, 05:45:39 AM »
Afraid I am unable to read the languages that are on the drives web site so not able to look at the specs, just wondering however if possibly you are needing to increase the Pulse width. Try setting to 5 for both pulse width and Dir prechange, if that doesnt work then try using Sherline mode.

For the Jogging it could possibly be that the Slow jog is set to less than 100%, you can either press the Tab key to see and change or press the shift key while you jog.

Hood
Re: motor madness
« Reply #2 on: October 07, 2009, 06:31:06 AM »
I've tried the pulse width/dir 5us change to no effect. the jog is set to 100%. Havent tried sherline though, i'll give that a go when i get near the machine again. As for the website its in german, a langiuage i am barely comprehending myself. I'll try a translation though  :)

SM44PCV5.1 driver board:

# Connectoors for 4 stepper motors
# Adjustable automatic current limiting. Current reduction at motor standstill
# Connects to PC parallel port or microcontroller
# Function check via LED's on each channel
# All inputs and outputs are across optocouplers
# signal current min. 3,3V
# pulse frequency max. 45KHz
# max. 46V Motor current
# 2A phase amperage (4A per Motor)
# with integrated fans
# Basismaterial-Epoxyd
# with soldering / stop paint and silkscreen (industrial grade)

   
Connectable limit switches and an active emergency / stop switch.
Four bipolar stepper motor driver (with a center tap unipolar) stepper motors can be controlled.
The circuit is designed for motors with 2A per coil. The max. Operating voltage is 46V.
The current limit is adjusted with a potentiometer for each channel so that the circuit is adaptable to various stepper motors.
Each axis is capable of a power reduction. Reduction is implemented when motors are at a standstill. Waste heat from the motors is greatly reduced. The current reduction is indicated by a LED. Four jumpers allows you to choose between full or half step. All external inputs and PC inputs are electrically isolated by optocouplers. All 4 axis on the control board can be operated directly via a parallel port on a PC or via microcontroller or any other TTL signal generating source. The control inputs can be connected via a 25 pin SUB-D connector to a PC. The motor connections arestable screw terminals with lift principle. Four axis limit switches and an active emergency / stop button can be connected. The status of the connected switch is signaled via LEDs and can be used as either internal or external display.


   
SMN4515V1 power supply:

The power supply board can operate with an input AC voltage of max. 30V AC and max 45V DC. The motor current is 15A, the 5V logic voltage can be loaded with 1A. The output voltages are indicated by LEDs. A large heat sink with an attached fan protects the board against thermal overload. The input voltage is secured with 15A fuse and protected by a surge suppressor against surges.


M5776/2.0/1.9 2 Phase High-Torque steppermotor:

# 2 phases
# Holding torque 1.9 Nm
# 1.8 ° step angle, 200 steps per revolution
# 8 wires, unipolar and bipolar switchable
# Nema 23, length 76mm
# 1 shaft, 6.35 / 1 / 4 "diameter
# Weight 1.0 kg
# Coil Current 2.0 A bipolar serial, parallel 4A
# Coil voltage 4.0 V
# Coil resistance 2.0 OHM
# Coil inductance 6.4 mH

Hope there's something usefull in there  :)

ps, the board uses an L297/L298N driver.
« Last Edit: October 07, 2009, 06:41:02 AM by deaddave »

Offline Hood

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Re: motor madness
« Reply #3 on: October 07, 2009, 07:05:00 AM »
Assuming you have it all connected properly then afraid I don't really know what else to suggest. I suppose there is a possibility that your computer is causing problems, have you run the driver test, do you have a scope so you can check the pulse is clean? but it sounds more like hardware issues
  Have you contacted the manufacturer to see if they can suggest anything?

Sorry not much help :(

Hood

Offline RICH

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Re: motor madness
« Reply #4 on: October 07, 2009, 08:45:41 AM »
Only did a quick read of what you posted. Two things come to mind from what you describe though.
- Automatic current reduction - see if there is a jumper to turn it off or extend the time before the reduction takes place as that has was a problem with a few some other boards.
- The other one is try lowering  the current setting or make sure it is correct for the motor wiring ( 2A). 
Again just a quick read of it all,
RICH

Offline stirling

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Re: motor madness
« Reply #5 on: October 07, 2009, 11:02:15 AM »
Did but a slightly slower read than RICH and I'm afraid not much of any of the specs actually makes sense or adds up so I think maybe there's a bit of a translation problem going on here. That said - generally speaking (I said generally speaking. So nobody out there kill me ok!) - out of the three possible ways of wiring an 8 wire motor for bi-polar drivers, serial winding is going to give you the hands down worst performance. If you can get better (English) specs that would be good. If your drivers and supply can handle it you'd be way better off with single coil and even better if you could go parallel.

The only other thing I can suggest is that sometimes (its happened to me) the wire colours are mixed up on the motor data sheets. Although the colour scheme you describe is common - I have seen them mixed up before now. Hammer drill is a good description of what motors sound like when this happens. A simple check with a multi meter will confirm they're correct.

Ian

EDIT: actually thinking a bit more, doh, a multi meter won't give you the full story - sorry. The attached piccy shows what I mean about mixed up wire colours. Here's two motors I use and you can see why one threw me. The labels A, A dash etc refer to the same colours BUT the START of the coils are on different colours. Get these wrong and your phases will freak out! The scheme you describe is on the right - you could try the left and see what happens.
« Last Edit: October 07, 2009, 11:42:22 AM by stirling »
Re: motor madness
« Reply #6 on: October 07, 2009, 01:59:09 PM »
Hood, you are a certified genious!

I tried the sherline setting, and every problem just magically went away, the motors are purring like very weird kittens, and on all 4 axis too  ;D
I shall manufacture a wooden kilt in your honour, once i get the machine built :)

Stirling, about the wiring, from everything else i've read you are right about performance. The wiring i had intended to use is bipolar parallel, but since i was just trying to get a working baseline i went with the serial wiring suggested by the seller. I dont have any datasheet on the motors but now that i know they work with that wiring, i'll have to assume the colors are right.

in that case it should be:
A: blu-blu/wht
B: red-red/wht
C: grn-grn/wht
D: blk-blk/wht
as you suggest.

The translation may indeed be lacking, german is not by any means a language i'm confident in. However with the board layout and the L297/L298N combo and a generous psu, pulling 2A per phase, 4A per driver should possible. I'll return with results. The board may be rather strange, but its fairly cheap and for reasons unknown the breakoutboard/driver selection avaliable in this end of the world is severly limited, that is, as long as you arent prepared to spend the GNP of Saigon on brand name systems :)

Offline Hood

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Re: motor madness
« Reply #7 on: October 07, 2009, 02:37:46 PM »
The certified bit could well be true but the genius definitely not ;D

Glad its going now.
Hood
Re: motor madness
« Reply #8 on: October 07, 2009, 03:40:15 PM »
Certified or not........certainly GIFTED !
I wasn't aware that you also did RESURECTIONS !
(very few have that power)
DeadDave is ALIVE !

Russ

Offline Hood

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Re: motor madness
« Reply #9 on: October 07, 2009, 03:42:16 PM »
LOL