Thanks Eddy, I think most of the encoders are incremental and some sort of homing is needed. As I understand, in the switch based homing, when the switch is triggered the encoder goes to Z which is one pulse per revolution. If one rev. =1.5mm movement, I assume that a switch repeatability of less than 0.75mm will do the job.
On my stepper based CNC the limit switches are wired in series with the e-stop and cuts the power to both spindle and steppers, not the electronics and triggers in mach3 an e-stop to pause the g-code. But with servos if both the drives and the controller have an e-stop input, which means double protection, is there any need to cut the power?
Do the drives have a Home and Index sync option.? Some drives will let you connect a switch to Home input on the drive and then they will sync the index pulse(z) of the encoder to position the motor.
What controller are you using.? Some controllers like the Cslabs will Home to index pulse or a set number of pulses after home switch detection.
Regards E-stop then you should always assume position is lost after hitting so therefore need to re-home to ensure accurecy. Like Eddy says E-Stop is emergency so should Kill power. Feed hold or pause or general stop is a controlled halt and doesn't lose or require homing.
Like wise a Limit trip isn't really an emergency situation it's a positional error so I wouldn't kill power to this action just halt drive outputs and inform controller it's happened. This will keep the drives powered and holding torque but really you will still have lost position thru inertia etc so homing will be needed.
I will most probably go with the CSMIO/IP-A.
The encoder has the index pulse. I don't think the drives have home inputs. There are CW Limit, CCW Limit and E-stop inputs. And an input called 'Zero clamp' I have no idea what it is for.
Is it safe to use only one switch on each axis side for both soft limit and home?
EDIT: where is the best place to put the home switches? For the X is it better in the middle? and for the Z?
Last edited by paulus.v; 16-02-2015 at 09:17 PM.
Last edited by JAZZCNC; 16-02-2015 at 09:20 PM.
I contacted star tech about using one of their usb to parallel adapters, I stated that it was to be used with a cnc machine and mach3 software the sales person went and had a word with their technical department and said for use with a cnc they recommend the ICUSB2321284 usb to parallel and serial converter is anyone also using this converter?
Thanks a lot for your help.
Last edited by paulus.v; 17-02-2015 at 08:41 PM.
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