3003
« on: February 25, 2014, 01:40:00 PM »
Ok well you have to reference the machine when you first start if you want soft limits with the IP-A as it needs to know where it is so it can set the soft limits. If you have persistent offsets chosen then you may think it will be the same position when you shut down and restart but I can guarantee it will not be and that has nothing to do with it being the IP-A. It will happen with any system whether servo or stepper. If you want to see you can simply press Reset and watch the DROs in Mach, they will change slightly and again when you take Mach out of Reset again, that is assuming of course you keep the encoders alive and are disabling the power stage of the drives.. The reason is you have forces acting on the axes, whether that be gravity or even just belt tension and as soon as you disable the servo drives they will not be holding position and the axes will move slightly, it may be a small amount but it will move. On a stepper system it will be similar, as soon as the drives are disabled the stepper will jump to the nearest full step of the motor.
So each time you do that you will be out by a small amount.
Now homing, the IP-A is capable of Index homing, you should use that as it is extremely accurate. What happens is the machine homes to the mechanical switch then reverses, when the switch again closes the axis continues until the Index pulse of the encoder is seen, that iis then your machine homed, it is the way almost every industrial machine homes and as said is extremely accurate.
Hood