Y axis slave issue

cncburn

cncburn
i have 2 Dmm servos on my y axis. I also have two home switches. I have the motors set with the Dmm software, tuned while not engaged to the rack. I verified the rotation and the homing switches activation. When I engage the racks, and try to home the system, the gantry moves ok for a short period and then seems to get out of alignment as if the servos are turning at different speeds. But I have confirmed that they are set to the same settings in the Dmm software. I have also had the direction of the one servo randomly reverse direction before ever getting to the stop. I have the y axis slaved to the B axis. I have even tried starting the home cycle and mannualy moving the gantry to the end to trigger the sensors before engaging the gear rack. Do you have any suggestions?.
 

masso-support

MASSO Support
Staff member
The motors should move the same way. unless the drive settings in the DMM drive are different, as a test can you please connect the STEP and DIRECTION signals of both the drives in parallel to the same axis connector on the MASSO so that its confirmed that both the drives are getting the same signals. Then please move this axis and check if both the motors run the same way.
 

cncburn

cncburn
Ok checked the direction and during homing the servos are moving in the same direction. But what was happening is that they were starting at different places on the dro. So I completed the homing without the drives connected to the gear rack. Then I slid the gantry to the end (0 position) I re set the power and homed and the drives turned together and ran together to the dro hard limit position. Thought it was interesting to note that even though the b axis is slaved to the y axis, the settings on both axis must match exactly.

Here is a problem still. If I jog the y axis, the b axis does not turn. The b axis jog does not work either. Yet during the home cycle, both turn. What am I missing?
 

masso-support

MASSO Support
Staff member
  1. Have to ticked the "Slave to Y axis" option in the B axis settings?
  2. Also have you setup and wired the B axis homing input from a sensor or a switch.
 

masso-support

MASSO Support
Staff member
Can you please email your MASSO settings file to support and also let us know what software version you are running, then we will setup a controller with your settings and have a look.
 

cncburn

cncburn
Issue not quite resolved yet. I think the problem is with my homing settings, but I also discovered that my servos were not stopping fast enough after the homing sensor was tripped. This resulted in a crash each time. Unfortunately, one of my drives blew out, during my axis testing. So until I get the issue resolved with DMM, I will not be able to proceed. Thank you.
 

masso-support

MASSO Support
Staff member
Please keep in mind that when homing once you trigger the sensor, the axis will take some dime to de-accelerate because you cant stop the movement at once. For this please simply mount the sensors sideways so that once triggered the axis can take some time to stop without hitting the sensor.
 
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