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Author Topic: Alright fellow campers...a frankenstein moment!!  (Read 6375 times)

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Re: Alright fellow campers...a frankenstein moment!!
« Reply #30 on: November 15, 2017, 08:39:01 PM »
Bob,
Not to be harsh, but your pictures give me an OH MY! moment as I have been building control panels for about 50 years. It is really easy to see why you are having noise problems. A couple of things really need to be done. The step and direction wires from the breakout board should be shielded or at least twisted in separate pairs of signals and commons. Same with the DC power to each drive. If the stepper motor wires are not shielded twist the four wires into a cable of sorts.  It actually helps if different pairs of wires are twisted in opposite directions and even different twist per inch rates.  Totally separate the DC feed and the motor wires from the drive signal wire. If they have to cross one another try to do it at right angles, don’t put them parallel. The number one mistake that everyone makes, including me way too often is a panel that is simply too small for all the stuff that needs to fit. That often leads to noise problems.
Re: Alright fellow campers...a frankenstein moment!!
« Reply #31 on: November 15, 2017, 10:46:50 PM »
Hi Gary,  nice to hear from you again.  I am going to replace everything with shielded wiring...so I will take your advice.  Now can I have 4 wires in a shielded cable etc., or do I need to have each individual wire in a shielded cable all by itself?

another question as someone said I might have mis-configured the a-axis.  For instance if I put in a360 f10, the stepper motor just clicks turns a partial mm.  Mach 3 is set for inches.  To get the lathe to do one rotation in say 7 seconds, it has to be set at f 5000.  So I am thinking I have  mis-configured something.  Also, could mis-configuring a-axis cause it to be super sensitive to interference, so that if it is reset properly, the interference may not be a problem?bob
Re: Alright fellow campers...a frankenstein moment!!
« Reply #32 on: November 16, 2017, 04:46:51 AM »
^ Put each pair of wires in a shielded cable, so if you have a switch or a DC motor, use 2 core shielded. A block of 2 switches can use 4 core shiielded. A 3 phase motor uses 3 core shielded and so on. The idea is for the current on one conductor to cancel out the magnetic field produced by the other while the shield reduces the effect of external influences. Equally, external RF and noise will affect both conductors equally and oppositely, reducing its harmful effects.  Just twisting pairs together goes a long way towards this, shielding increases your margins even further.
This goes both ways - shielded/twisted wires will radiate less trash signal than loose single cores.  ;)
Re: Alright fellow campers...a frankenstein moment!!
« Reply #33 on: November 16, 2017, 05:59:25 AM »
To Rich, Chaoticone, Gary, 

I did an experiment which got a different result.  I took my x-axis stepper driver and switched it out so that it is now the A-axis stepper driver.   I left the X-axis simply unconnected for this test.

I took the wiring from a-axis and wired it to the new stepper driver.  The problem ceased.  The spindle when activated did not active the lathe.  So could I have purchased simply a defective stepper driver???  The stepper driver that I bought for the A-axis and seems to have the problem is a Microstep brand driver STM5045.  I am ordering a new stepper that is the same as all the original steppers as x-y-z axis use.  I redid this test 4 times and got the same results, so it appears to be duplicating either the malfunction if I use the Microstep driver, or no malfunction when using the original x-axis driver.  I am afraid to put the Microstep driver on the x-axis as it might do something weird...  what are your thoughts on this?  Do you think this may be the problem?

To BluePinnacle--thank you for your advice on the wiring.  Bob

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Re: Alright fellow campers...a frankenstein moment!!
« Reply #34 on: November 16, 2017, 06:30:34 AM »
Bob,

Quote
To get the lathe to do one rotation in say 7 seconds, it has to be set at f 5000.  So I am thinking I have  mis-configured something.
I will be covering feedrates in the next lesson.

RICH

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Re: Alright fellow campers...a frankenstein moment!!
« Reply #35 on: November 16, 2017, 08:25:12 AM »
Bob,
What brand drives are used for the x,y,z axes?

I suggest you not buy another drive. The problem may have to do with  control box wiring and the box itself and not the drive as others have implied. Sorry I didn't look at the pic's you posted earlier and more closely.

Keep it connected as it was.

It looks to me that you controller box has bottom and two sides metal and the other two sides wood.
Don't know what your using for the top of the box. Simply said the box is not shielding anything.
ie; Wood does not keep the "rain" from getting in!

Consider how any connections are made when they penetrate the controller box.
ie;No seal around the pipe penetrating the wall allows the water outside the foundation wall to leak in. A hole thru the box with wire running through it does not allow for continuous shielding. ie; wire shield on cable bonds to box at connector and the rf ground system  provides a path for noise from the box to ground which presents little resistance to the noise.

On the end of the radio's antenna you  can wrap a coil of wire. You cover the coil and also some length of the actual antenna with something  non -conductive. The allows you to get very close to a spot, not make an electrical contact, and inductively pick up the signal / noise.

Go "sniff" more  at any wire penetrating the box. In particular sniff the the  A axis wires.
If noise mixes with output wires to the stepper it can be the equivilant of sending pulses to the stepper.  

Gary was nice in his post......
I express the condition in this way:
All dishes and utensles are washed and dried before putting them neatly and orderly on the dinning room table in preparation for the meal. This is done before the guests arive for dinner. ;)

RICH

 
 
 
« Last Edit: November 16, 2017, 08:30:32 AM by RICH »
Re: Alright fellow campers...a frankenstein moment!!
« Reply #36 on: November 16, 2017, 03:11:45 PM »
Rich HI,  ok I get the picture... will start on this.  Thanks bob
Re: Alright fellow campers...a frankenstein moment!!
« Reply #37 on: November 16, 2017, 04:13:22 PM »
Rich the stepper drivers are DM556D.
Re: Alright fellow campers...a frankenstein moment!!
« Reply #38 on: November 16, 2017, 05:36:13 PM »
Question:

the info on the stepper motor for the lathe says 3.0 amps,  the stepper driver which causes the lathe to move when the spindle is turned on is set for 3.0 amps.
The other drivers are all selected for 3.2 amps.   Now as I said and I tried it again this morning.  When the wiring for a-axis is set on another driver beside the one that has problems, then the problem of interference stops.  So could it be that my selection of 3.0 amps on my mal-functioning driver should be set higher... its next choice is 3.5 amps... it does not have the choice of a 3.2 amp setting.

Also the ST-M5042 driver (the malfunctioning one) cost about $35 bucks.  and the best price on the dm556D driver is like $50 off of ebay.  So maybe there is a real quality difference???
Re: Alright fellow campers...a frankenstein moment!!
« Reply #39 on: November 16, 2017, 05:51:00 PM »
Also on all the drivers there is a note about switch 4 being on = half current and switch 4 being off, equals full current.  What does this mean???  bob