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View Full Version : AM882 and Nema 23 Tuning



thorphar
29-09-2014, 01:28 PM
I have finally got my BOB working with mach3 and managed to get the stepper to turn. My set up includes AM882, Nema 23 and a ZP5a-INT BOB. However I have no idea how to go about tuning this stepper and driver config using the dip switches on the driver or on mach3 itself. Please could i get some advise on tuning the motor to allow it to run smoothly. I have added a link below to a video that shows what the motor is turning like at the moment.

Any help would be much appreciated.

https://drive.google.com/file/d/0B6vERS9G-YolN0VQVF9mWmM1UkU/edit?usp=sharing

EddyCurrent
29-09-2014, 02:47 PM
You've rolled several things up into one here.

1. Which wiring method for the motor did you choose ?
2. Setting the AM882 to match your motor
3. Setting the values in Mach to match your hardware
4. Tuning the system

What voltage is your power supply feeding the AM882 ?

With the AM882 you can configure it using the switches or using ProTuner, you said using switches so;

1. connect the motor for 8 lead parallel, see your motor data sheet.

2,Determine from the data sheet the max current for the parallel connection.
Set on the AM882, (SW1, SW2, SW3) to the next lowest setting of max motor current. e.g. if your motor data sheet said 3 amps then the next setting down on the AM882 is 2.7 amps.
i.e. SW1 OFF, SW2 ON, SW3 ON

Next leave SW4 OFF
Set the rotary switch to 0 (zero)

Set SW5 OFF, SW6 OFF, SW7 ON, this sets microstepping to 8 which is a popular setting.
Set SW8 OFF

3. In Mach 3 set the Velocity to 2000, acceleration to 200 (these will do for a start)

From your motor data sheet get the degree movement, normally 1.8 deg.
From your ball screw on the machine, get the thread pitch. (if you don't have this yet just use the value 5 as below)
calculate 'steps per' in Mach 3 as below using those values you just found.
Step and dir pulse, I've tried different values here and it seems to makes little difference with the AM882, leave as default.

step per = "The number of steps Mach3 must send for one unit of movement"

So for a metric machine one unit of movement = 1 mm;

a 1.8 deg motor has 360 / 1.8 = 200 steps per rev.
with microstepping set to 8, 200 x 8 = 1600 steps per rev
with a screw pitch of 5mm, 1mm movement = 1/5 turn
1600 x 0.2 = 320 steps per

All of that assumes a 1:1 ratio between motor and leadscrew
There are other settings in Mach3 like 'kernel speed' and I'm assuming you left these at default settings.


I would expect the motor to run smoothly now.

4. Tuning can only be done once the motor is fitted to the machine and it is ready to go.

JAZZCNC
01-10-2014, 11:24 AM
Ok well thats strange movement even if you had some switches wrong on drive so I think you may have motor phases wrong.? So can you post the wiring colours you have paired up. (and motor model)

Also I see your using a Laptop but you don't mention anything about Motion control card so I'm going to presume your using the Parallel port. Laptops shouldn't be used with the Parallel port as they cause all sorts of strange affects.! It's because of the way Laptops deal with saving power and also the fact they don't often come with 5V parallel ports and most are 3V which affects the drives in strange ways like this as there's not enough Logic differance in pulse strength so drives get wrong signals etc. If you look in the Manual or On Web site Artsoft state not compatible with Laptops unless using Exteneal motion control card and this is because of the irratic nature of using Laptops, some work, most don't.!!

Eddy's settings are correct except he's assuming your using Mach3 in Metric and I can see on the Video you have it set to Imperial as the feed is set to 6 and the way the motors moving that must be 6"min not 6mm. If you change to Metric in Native units then you must restart Mach and retune the motors.

The AM882 as feature that lets you auto tune the motor to drive by flicking switch (4) - 2 times in 1 sec but I find this awkward using the Switches so prefer to connect thru software using Protune. In Protune you can also set the Motor amps spot using the Current setting as it's setable in 0.1A increments. Using Protune takes any guessing away and you can also play with the tuning better and fine tune the machine if you want to. (The motors must be on the machine thou to do this properly)
You must set the rotary dial on the drive to (0) if using flicking the bean method or Protune.

One more thing while testing on the bench it's best to clamp the motors other wise resonance affects the motors!

thorphar
01-10-2014, 12:12 PM
Ok well thats strange movement even if you had some switches wrong on drive so I think you may have motor phases wrong.? So can you post the wiring colours you have paired up. (and motor model)

Also I see your using a Laptop but you don't mention anything about Motion control card so I'm going to presume your using the Parallel port. Laptops shouldn't be used with the Parallel port as they cause all sorts of strange affects.! It's because of the way Laptops deal with saving power and also the fact they don't often come with 5V parallel ports and most are 3V which affects the drives in strange ways like this as there's not enough Logic differance in pulse strength so drives get wrong signals etc. If you look in the Manual or On Web site Artsoft state not compatible with Laptops unless using Exteneal motion control card and this is because of the irratic nature of using Laptops, some work, most don't.!!

Eddy's settings are correct except he's assuming your using Mach3 in Metric and I can see on the Video you have it set to Imperial as the feed is set to 6 and the way the motors moving that must be 6"min not 6mm. If you change to Metric in Native units then you must restart Mach and retune the motors.

The AM882 as feature that lets you auto tune the motor to drive by flicking switch (4) - 2 times in 1 sec but I find this awkward using the Switches so prefer to connect thru software using Protune. In Protune you can also set the Motor amps spot using the Current setting as it's setable in 0.1A increments. Using Protune takes any guessing away and you can also play with the tuning better and fine tune the machine if you want to. (The motors must be on the machine thou to do this properly)
You must set the rotary dial on the drive to (0) if using flicking the bean method or Protune.

One more thing while testing on the bench it's best to clamp the motors other wise resonance affects the motors!


Thanks for all the advise, however the motor is still refusing to turn smoothly. I did not really explain the set up too well. I am running a old foxconn desktop to control the cnc machine and using my laptop (mac) as a wireless monitor and keyboard using a simple rdc and self dedicated wireless router. I have now clamped the motor to the table. I have attached below a image of the wiring and model names.

http://www.mycncuk.com/attachment.php?attachmentid=13513&stc=1



http://www.zappautomation.co.uk/productattachments/index/download?id=98

JAZZCNC
06-10-2014, 11:13 PM
Ok well every thing looks ok wiring wise but I would dump the PC/Mac setup and use dedicated PC setup.

Set the drives up using the settings Eddy provided.

Then as a little test using this PC/Mac setup try this. Go to MDI screen and type G0 x100 and see how it moves. (G0 is G (zero) not "O")
If you still have harsh movement then I would try another PC setup before doing anything else.