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[JAZZCNC]

yet another question - How do you pick the resolution to use (microsteps) for carving wood? Example: I have 2 DM542s and one DM860. DM542 range from 2 to 128 Microsteps and 400 to 25600 Step/rev.(for 1.8* motor). DM860 2 to 256 Microsteps and 400 to 25600 Step/rev.(for 1.8* motor).

Ok well first 2 to 128 and 400 to 256000 are the same thing just using a different notation. Let me explain.!!

Typical Stepper motor needs 200 FULL steps for one revolution. (360/1.8=200) These FULL steps can be broken down into micro steps by the drive electronics.
So first notation uses 2, 4, 8,16, 32, etc which means 2 x 200=400 micro steps or 4 x 200 = 800 microsteps etc.
The second notation uses 400, 800, 1600, 3200 etc which is the result of the above calculation.

Both mean the same thing.

Now like most things CNC which is best isn't straight cut thing.? There are several factors which have to be considered and they don't relate to the type of work your doing with the machine.!! The things that affect micro stepping setting are the PC your using or better put the motion control device your using ie parallel port and the Machine it self.

The strength of the machine and Resonance can play a big part in what micro stepping works best for your machine and the motor/drive relation ship so resonance doesn't affect them and some trial and error can be needed to match your motors best.

Then you have the PC to consider, or more important the Max number of pulses your parallel port or motion control devise can reliably give out.! This is a very important consideration for relaibilty, accurecy and performance you'll get.
If you set the micro stepping high then you'll require many many times more pulses to reach the same speed as a lower micro stepping setting. For instance a setting of 400ms will require 6666.666 pulses per second to reach 1000rpm at the motor. For the same 1000rpm with 1600MS you'll need 53,333.333 pulse per second
If your pulse device ie parallel port then you'll only have limited amount of pulses available which with standard mach3 setting will be 25,000 pulses per second per axis.
Has you'll see this is fine for the 400ms setting with some pulses to spare. But with 1600 you'll only have half the number needed to reach 1000rpm so therefore the Max speed you'll achieve is 500rpm. So going too high can limit speed depending on the Pulse rate the Motion control devise can output.

So you'd think OK I'll keep MS low but again it isn't always that simple as the closer you get to the FULL step of the motor the rougher the motor tends to run and resonance becomes a problem. This is why the Minimum MS amount is 400 or 2 x 200 as running full step isn't fun.

So higher MS helps to smooth out the motors and deal with resonance. The trick is picking a MS setting that suits the machine and resonance to give a nice smooth motor without stressing the pulse device.
If you stress the pulse device and overtune the motors you'll lose steps and accurecy.

Common Setting is or starting point is 800ms or 4x and if the motors stall easily or sound resonant and rough running then try different setting.
Remember every time you change MS setting you'll need to adjust the Steps per setting so machines moves correct distance.

Sorry for long explination but your better knowing why than just wondering why.!!

[shipper506]

For some reason the thank you message did not go through so here it is - Thank You for that information. You have explained it well. The next problem I am having is setting up Mach3 Ports and Pins "Motor Outputs". The simplest way to ask this question is: Is there a way to determine which pin is motor and which pin is direction for each motor? What is printed on the breakout board is as follows:
Pin Label
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

I have assumed the "+" is the "Step Pin#" and the "-" is the "Dir Pin#".
(again Thank You All for listening to the ramblings of this old man)

[JAZZCNC]

Ok well you should have Dir and Step + & - for each axis. Or at least Dir & Step plus one more connection for either ground or 5V (often marked Vcc) depending on the connection type you choose on the drive. common Anode(NPN) or Common Cathode(PNP).

What BOB and Drive are you using.? I'll take a look for you.

[shipper506]

OK if this worked you see what i call the brains of my CNC machine: pic1 is in it's sleep mode - pic2 working state - pic3 is the Dell computer - pic4 is the slide out that holds the power supplies, CNC stepper controllers , and the breakout board - pic5 is the breakout board.

[shipper506]

correction to previous post it is NOT:
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

it IS:
2 PUL - X
3 Dir - X
4 PUL - Y
5 Dir - Y
6 Pul - Z
7 Dir - Z

[JAZZCNC]

correction to previous post it is NOT:
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

it IS:
2 PUL - X
3 Dir - X
4 PUL - Y
5 Dir - Y
6 Pul - Z
7 Dir - Z

Ok well those pics are about much use as fart in space suit but I think I get the problem.!

The BOB will have a 5V output supply. Take a wire from this to each of the Step & Dir (+) on the drives. This should get you working.

[shipper506]

If you look close at pics 4&5 you will see a brown wire with a white stripe on one side (looks almost like a white wire) going from the 5vdc+ on the breakout board to the PUL+ and a jumper from PUL+ to Dir+ on each controllers. I have put a volt meter on all three and they all have 5vdc power. I also checked all three power supplies and they all have the proper power output. I rechecked all connections and wires to be sure they are all in the proper places.

[JAZZCNC]

correction to previous post it is NOT:
2 Dir + X
3 Dir - X
4 Dir + Y
5 Dir - Y
6 Dir + Z
7 Dir - Z

it IS:
2 PUL - X
3 Dir - X
4 PUL - Y
5 Dir - Y
6 Pul - Z
7 Dir - Z

Right then you have it wired correctly. So now just enter the corrected pin numbers into mach3 motor outputs for step and direction of each axis. Don't forget the port number which will most likely be 1. Also make sure enabled is ticked.

[shipper506]

I have to work the next 7 days strait so i will not be able to physically work on the machine but i will be reading about the setup and maybe i missed something. I'll let you know how it goes.
A side note: I did notice the X and Y steppers get warm when its on for more than an hour or so. I set them all for half power when stopped.