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Author Topic: Looking for good DIY controller kit supplier  (Read 4050 times)

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Re: Looking for good DIY controller kit supplier
« Reply #120 on: December 04, 2020, 09:59:58 PM »
I follow the noise rationale

Every cable on my CNC is UNshielded. I will replace all with shielded twisted pair cable; as said before - not too expensive.
Pls advise though, is 0.4 mm 4 core suitable for the steppers or should it be 0.5 mm precisely?

The 24V power supply I've ordered is a direct equivalent to the LRS-350-24  but 400 instead of 350W.

Thanks for the layout drawing. I'm installing everything on the outside of my wooden computer hutch. 15 mm thick ply and a further 200 mm away from the nearest computer cable. Should be nil noise. I've decided to put it there as there is maximum chance of air cooling. The system is in a shed, which during summer times hits 42 degree C.

Some questions:

"I was going to use a solid state relay for the spindle but decided not to. It would have meant using P17 which is shared with the onboard relay, that's why the relay jumper was OFF. However I'm using the small onboard relay to control the spindle relay so it needs to be ON".
; I do not really understand this, MN300, where is the small onboard relay?

On the BOB connectors; what do CW and EM stand for?

On the 24 V Power Supply; what do L and N stand for?

Just below is a squiggle with F1 and 2A; what is the squiggle and what do F1 and 2A stand for?

On the 230 VAC; this is mains power, is it not? What does the E stand for?

On the TB6600; what do ENA and VCC stand for?
Re: Looking for good DIY controller kit supplier
« Reply #121 on: December 04, 2020, 11:17:51 PM »
Y or N; 4.5 V 500 mA instead of 5 V power supply?

Offline MN300

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Re: Looking for good DIY controller kit supplier
« Reply #122 on: December 04, 2020, 11:22:35 PM »
0.4 mm2 is OK.

What's the model number of the 400W supply?

When the temp gets into the 30's blow air over the stepper drivers. The maximum ambient temp for the motors is 50º C.
 
In one corner of the BOB photo there is a blue box. That's a small relay that is activated by a signal on P17 when the jumper is installed. I have used it to switch 24V to the optional relay for spindle power. 

The different pieces of equipment use different names for the same signals.
DIRECTION = DIR = CW (CLOCKWISE)     ENABLE = ENA = EN     PUL = CLK (clock) = STEP

L = LINE, the wire that carries 240 volts  N = NEUTRAL , The wire that returns the current from the 240 line. It is connected to earth at the source. If it loses that connection to it could be energized by the 240 line through the connected devices and be hazardous. That's why a separate earth connection is used as the safety ground. E = EARTH This line is connected to exposed metal parts to prevent them from being energized if accidently connected to voltage.

The squiggle is a fuse named F1, value shown is 2 amps but that might be increase when I see the supply info.

VCC = voltage, common collector. It's the supply that powers the logic. That's the 5V supply in this case. The name is a carry-over from the early days of logic IC spec's.

No to 4.5V
Re: Looking for good DIY controller kit supplier
« Reply #123 on: December 04, 2020, 11:53:11 PM »
Thanks for the answers; illustrative.

24 V power supply from Geekcreit S400-24

I have a 240 V as well as 24 V computer fan; which would be the best to fit, considering 'noise'.

value shown is 2 amps but that might be increase when I see the supply info; by 'supply info' you mean the specs of the Geekcreit S400-24?

5 V it is

Offline MN300

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Re: Looking for good DIY controller kit supplier
« Reply #124 on: December 05, 2020, 12:09:30 AM »
Neither fan should cause a noise problem, use the one that moves the most air.
Yes, the fuse is for the 24V power supply.

Offline MN300

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Re: Looking for good DIY controller kit supplier
« Reply #125 on: December 06, 2020, 08:56:30 AM »
I have been revising the wiring diagram, adding information on the selected 24V supply and some notes. I’m sure it’s not finished yet but I’ll attach what I have so far to help with the following discussion.
 
Here are some PDF file links for reference.
Microstepping
https://motion.schneider-electric.com/technology-blog/stepper-motor-basics-half-and-micro-stepping/

TB6600 stepper driver manual
https://forum.arduino.cc/index.php?action=dlattach;topic=558523.0;attach=266385

I added notes with suggested starting values for stepper current and microstepping. After the machine is running we can change them to your final settings.

I chose times 4 microstepping to improve the smoothness of the stepping. This decreases the mm/step  and increases the steps per second  rate from MACH 3 by the same factor. If the higher rate is problem we will have to reduce it.

A more careful reading of the manual revealed my assumption about the ENA input was incorrect. In fact powering that input turns off current to the motor! I think it would be more correct to call it a disable input.
One of the connection options shown is to not connect anything to the ENA terminals. This would leave the current on at all times. The disadvantage of this is that the motor would consume about 40 watts of power in standby. However once the machine is zeroed you wouldn’t want to turn off the current. Doing that would result in the motors pulling to the nearest full step position. Unless you spend a lot of time with the machine powered and idle not using the ENA inputs makes sense.
By the way, this explains why overloading the BOB enable outputs is not a problem. No current is taken from the BOB when the motors are in use. If there is a failure it would be the inability to turn off the current.

I realized a quirk of the BOB board makes it possible to use an E-STOP switch with only one NC contact. The 24V supply powers the opto couplers for the inputs. Turning off the 24V has the same effect as opening the normally closed E-STOP switch. With this method the BOB’s E-STOP input would be wired directly to GND.
Re: Looking for good DIY controller kit supplier
« Reply #126 on: December 07, 2020, 04:18:28 AM »
Thanks MN300, I'll pore over the micro stepping article and TB6600 manual.

Drove the distance to Jaycar today, lousy customer service but came back with the following:
E Stop - https://www.jaycar.com.au/latching-emergency-stop-switch/p/SP0786
5 V power supply - https://www.jaycar.com.au/5v-dc-3a-slim-power-supply-7dc-plugs/p/MP3480
Terminal block for 24V supply from BOB to TB6600s
but no cable. "Look in the catalogue" was the reply, at a cost of just under $6.00; so ordered the cables from a very helpful person at Makerstore P/L - awaiting delivery.

Also received by post: BOB and 3 TB6600s. I opened the driver up to see if it truly had a TB6600 chip, and it does.

I'll read up on the ENA in the manual to follow your rationale and I see what you mean re the EStop if it is as per attached pic
Re: Looking for good DIY controller kit supplier
« Reply #127 on: December 07, 2020, 05:56:08 AM »
I see the microstepping now. The 1.8 degrees is determined by the number of 'teeth' of the permanent magnet on the rotor, the step is activated by an electromagnetic field in the stator. Direction is determined by polarity with change of direction determined by change in direction of current applied to the stator. Rate and step size of rotation is achieved by playing multiple windings (Min 2) off against each other in terms of current strength, direction and sequence. I'm still to fully understand Phase Current Waveform. 

Offline MN300

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Re: Looking for good DIY controller kit supplier
« Reply #128 on: December 07, 2020, 09:32:36 AM »
The power supply you selected has 3 terminals each for V+ and V- , you can connect the stepper drivers directly to the supply. Some of those terminals will be shared with wires to the BOB, also for the relay if you choose to control the spindle. The terminal strip you bought may be useful for other wiring like the AC mains circuits and E-STOP.

Is the cable you ordered for connecting the power supply to the TB6600s?
You stated earlier that you would like to use the 4 pin connectors for stepper driver signals. To do so you need cables with the mating plugs attached.  Have you found a source for them or the materials to make them?  It would be easier to use the cables from the now unused encoder and wire to the BOB terminal strip.

You mentioned phase current waveform. It can be explained with Trigonometry and vectors. If you graph a vector rotating through 360 degrees you get a sine wave. This is like a stepper motor moving from one pole to the next. The current in one winding would be the sine, the other the cosine. Together the two currents create a rotating magnetic field that pulls the rotor in a circular path. The vector sum of the currents is always the same while as resultant position changes.

https://upload.wikimedia.org/wikipedia/commons/8/89/Unfasor.gif
This animation may help. The sine being generated is the position of the rotating vector in the X axis. If the Y axis position was graphed it would be a sine wave 90 degrees out of phase. These two waves represent the currents needed to make a rotating field.

Offline MN300

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Re: Looking for good DIY controller kit supplier
« Reply #129 on: December 07, 2020, 12:01:39 PM »
Here is another revision of the wiring. Unless you decide to use the BOB terminals instead of the 4 pin connectors it could be the version you will use to wire the machine. After the machine is setup and running we can make the final revisions.

This version uses a single E-STOP contact and does not use the stepper enable signals.

I imagine you will use a power strip to distribute the mains power so I have added that. The spindle would plug directly into the power strip if you choose not to install the optional relay.

Jaycar and Maker Store don’t have the fuses and fuseholders needed so I used element14.

Fuseholder
https://au.element14.com/littelfuse/01500332h/fuse-holder-6-3x32mm-15a-500v/dp/2748639

Fuse
https://au.element14.com/bel-fuse/3sb-5-r/cartridge-fuse-slow-blow-5a-250v/dp/2844478