View Full Version : AM882 strange sensorless stall detection issue

18-12-2015, 05:01 PM
Im having trouble setting up my drives to my motors. Im using protuner and have not tried using the dip switches. ive got the 4nm motors from cnc4you and it says max current is 4 amps.

So ive setup pro tuner as follows
ive even tried the max current at 3 amps which seems to make no difference. I know it should be 4amps but im just guessing at things now.

The major problem is it keeps tripping the sensorless stall detection even on the x axis where the belt is not even installed on the pulley. Sometimes (but very rarely) ive had it move the z axis (thats linked up with the belt) and the x axes motor only. All the motors seem to move freely.

Can anyone help as im out of ideas why at the moment.


18-12-2015, 05:13 PM
You 100% sure it's Stall detect because it only works above 300rpm so if it's not even moving then it won't be that.!! Have you counted the flashes.?

If this is happening all the time and has done since fitting then I be more inclined to think it's a Phase fault.

Have you tried swapping the drive with one that's working.?

18-12-2015, 06:40 PM
Hi Jaz thanks for the reply, i tried a different usb to serial cable and it all came to life which is great. :anonymous:

it even stops when it hits the limits. Although once when it hit the limit (it cuts the enable signal) then the drive did report a stall. could this be due to it running along (not very fast) and then stoppping dead when the limit takes away the enable? If so is there away to stop the stall, may have been a one off as i havent tested again.

Just really happy all my axes work :fat:

18-12-2015, 07:14 PM
Hi Jaz thanks for the reply, i tried a different usb to serial cable and it all came to life which is great. :anonymous:

USB to Serial.?? What you using for Motion control.?

it even stops when it hits the limits. Although once when it hit the limit (it cuts the enable signal) then the drive did report a stall.

Again are you sure it's reporting a Stall.? . . . Should flash 5 times.

18-12-2015, 07:24 PM
Yes I was using it as my laptop does not have a serial port so I had to use it when using protuner. For the motion controller I'm using csmio/ip-m. I've done some initial setup but not alot as I wanted the drives to be programmed first.

I'll try it again tomorrow.

Thank again Jazz for your help


Mammoth 01
04-01-2016, 04:34 AM
Hi Gotty 101,

i have been been working with Jazz for some help and thought possibly I could get u in on this as well since you seem to be further along than I am with your Am882 drives. I can make my motors move from pro tune but not my BOB.

I am am scrambling for help on this. Considering bagging the Am882 drives and going to gecko digitalis for the tech support they offer. The am882 is not offered in the states by Leadshine so they will not help at the USA office. I am hoping I didn't get bum drives from China!!!

What at settings have you used in Mach3 and the pro tune to make these damn things communicate with each other. I am not using either the alm or the enable on the 882 at the moment. I am running a PMDX 126 bob only hooking up one drive and on motor. Tried various settings in Mach motor out puts.

Possibly you would have some ideas to go along with what jazz has been giving me, and I can get this sorted out. You set up looks great by the way!


ben bouch

04-01-2016, 08:51 AM
Hi Ben,

Thanks for the message. i will try and help as best i can, although JazzCNC is very much a guru on here and he knows his stuff and has far more real experience.
If you can make your drives move in pro tune thats a good sign, so its unlikely you got any bum drives from China.

One setting i had trouble with is the active high active low setting. On my cnc i control the enable signal so if the enable contacts are being fed 5v then i wanted the drives to be enabled, i found the description next to the checkbox in pro tune unclear/badly worded. But all in all if your drive is ready to go, and is enabled the red led will be off and the green power led will be flashing. Are your drives like this?

Also in protune once you have made the changes you wish to keep do remember to use the write to eprom button, otherwise when the power is cycled it will forget your new settings.

next basic thing to check is your wiring between your bob and drive, make sure your only feeding 5v into the dir and step pins on the drives (they are optoisolators, and your just lighting the led inside it so dont feed more unless you have used the correct current limiting resistor).

Mammoth 01
04-01-2016, 01:40 PM
Hi Gotty,

Yes It is all set up that way. I have installed +5v to Dir= and Pul+. I am not using the enable or Alm but wondering if I have to run a +5 V to the enable. The drive shows no errors and is blinking green ready to go. Like I was saying its weird I can run the motor from the Pro Tune pulser but not my Mach3. I know that the box in pro tune Dir DEF has some play in this. I believe that I have it selected low. I have wrote the eepromp as well. I will try to reset the drive in Pro tune and put all the switches in the default next, and re set up the pro tune. I have tried so many different combinations its driving me nuts.


Mammoth 01
04-01-2016, 01:41 PM
A corretion in my typing that was DIR+

07-01-2016, 06:32 PM
If the green light is flashing then its good to go and you dont need to worry about the alarm and enable for now.

One clear difference running from mach and pro tune, is pro tune is going direct into the drive where as mach is going via the bob. From your description, your feeding +5 to step and dir pins on the drive and im guessing the step and dir - pins go into your bob? Are you sure the bob is wired right? ie is the dir - ment to be wired into the bob, meaning its syncing and not sourcing?



29-06-2016, 09:13 PM
I'm new on MYCNCUK, just joined.
Let me please share my experiences with AM882 and 4Nm motors from cnc4you.co.uk.
I bought AM882 from Ebay china, and got 2 version, two was V1.1 other 1.0. (the last digits in serial number is MS11x, or MS10x, x=with one letter, in my case is K and C.)
Based on my testings version 1.0 have stall detection working exactly upper 300RPM, but for V1.1 stall detection started to work at 180RPM.
But when tried with the 4Nm motor from cnc4you after auto tune the stall detection isn't work when set current above 2.5A. Tried with other motor worked well.
I got really confused but I found a work around to solve the issue on this way:
After auto tuning I saved the configuration file with pro tuner and the motor coil resistance was as I remember about 1.1....1.2Ohm, which is real.
Opened the config file with notepad I edited the resistance value to 2 Ohms, and uploaded to the driver and saved in eeprom. Now the stall detection is working very well with nema 23 4Nm motors from cnc4you with current set to 3.5.....4A.