sivtek wrote:Thanks again Dave.
The "Set TP TLO" now works fine!
Good.
sivtek wrote:
Maybe you can give me some hints on referencing the axis? In my old system (Windows XP and no SmootStepper) the system did work OK.
My mill is a SIG KX3 mill. BOB is C11G - multifunction board and SS is V1.2 with USB connector. In the SS I have adapt 1kHz as Controller Frequency and the MaxStep Frequency to 32 kHz on all axes. Also in Mach 3, General configuration Dialog I have tried Debounce Interval 200/1000/10000.
Sometimes the table go to the switch and stay there, other times it go to the switch then back of and continue to do so, will not stop backing off. ?
Can it be a SS issue?
It could be an issue that started when you changed to the smooth stepper. However, that does not means the problem is with the smooth stepper itself. Rather, I would suspect that this is a system problem that the change to the smooth stepper makes more visible.
I'm not sure what you used before the smooth stepper, but I'll assume it was a parallel port.
My guess would be that you are experiencing an electrical noise problem. Electrical noise on the input lines from the home switches can make the system act as if the home switch is triggered before switch is physically activated. It can also make the electrical edge of the input signal when the switch is triggered (and un-triggered as it backs off) be missed by the system. Noise often shows up as unstable operation of input signals. Homing is a typical area where a problem is seen because to home you have to be running the motors - and running the motors causes electrical noise. An input signal may look fine with no motors running but fail when motors are running. If you are using a VFD on the spindle, they can cause lots of noise also.
Why can this happen with the smooth stepper? A common reason is that the smooth stepper is a USB device. The use of the USB cable interconnects the PC ground to the smooth stepper - this can cause a difference in the ground configuration of the control system when compared to the configuration of a parallel port system. What is needed is a scope and some time looking at the input signals for the home switches. You want nice clean sharp transitions when the switches activate/deactivate. I would also mention that noise immunity this is a reason that the ethernet smooth stepper is preferred by some over the usb smoothstepper.
You will never get perfect signals because (particularly mechanical) switches "bounce" some when making contact which results in several short high/low pulses at the input pin. It is best to electrically filter this to remove the bounces on the input signal. If you can't do that, mach provides the "software debounce" feature to help. What that does is make mach see a steady input signal for a period of time before the input signal is recognized as being active. The period of time is what you are setting when you set the bebounce interval value in mach's config. Each unit of debounce is typically 40 micro-seconds. If you use a lot of debounce, the axis motion continues until mach sees a steady input state for the entire debounce time period. From the debounce interval length and the axis speed you are using to home the axis, you can calculate the amount of overrun that the axis will travel before the home switch input is seen by mach as being active. A fast home speed and a long debounce time can result in physical damage from traveling past the home and/or limit switches. This is why fixing electrical noise is better than using software to ignore the noise via software debounce.
This type of issue is usually an electrical problem. You'll need to debug the electrical signals to sort it out. Other than that mach's debounce ability, there is not much that can be done in software to "fix" this.
Dave