Jog Speed vs Homing Speed

[deanr181]

Hi guys,

Finally got to setting up the homing function and seem to have run into a problem.

The homing function works fine as long as i am moving very slow (3000mm/min). I am using mechanical limit switches.

If I go any faster, the limit switches will still detect and start to back off the axis, however it is backing off very very slow and then i get an Axis Alarm due to the axis not backing off enough to reset the switch. I didn't realise this was a timed function?

I also notice that the Jog speed is set at the same speed as homing in the Axis setting.

It will take forever to do an auto tool change at the back of the machine, then come to the front of the machine to set the tool height and then go back to start cutting.

Is there anyway we can set the jog speed higher without affecting the homing speed, or preferably, how do i get the Axis's to back off quicker?

Hope you can help as this needs to be resolved.

Thanks

Dean

 

[breezy]

@deanr181

Dean,

The homing function works fine as long as i am moving very slow (3000mm/min). I am using mechanical limit switches.

If I go any faster, the limit switches will still detect and start to back off the axis, however it is backing off very very slow and then i get an Axis Alarm due to the axis not backing off enough to reset the switch. I didn't realise this was a timed function?

That's correct, if you set the homing feedrate too high you will overrun the switches. Masso backs off at a very slow rate for a certain distance looking for the switch to "clear" and then it moves the backoff distance set in the homing screen. As MASSO knows nothing about the inertia of you machine it just assumes that the switch will be cleared within it's internal backoff distance.

I also notice that the Jog speed is set at the same speed as homing in the Axis setting.

Is there anyway we can set the jog speed higher without affecting the homing speed

Jog feedrate is set in the axis setup screen and has no correlation to the homing feedrate. You set the max feedrate when you calibrated your axis.

Regards,

Arie.

 

[deanr181]

Thanks Arie,

What I notice is when I set the Axis speed, the homing and jog go the same speed.

If i increase the speed, the jog goes faster and so does the Homing. This is the problem. When homing at a faster speed, it over runs the switch further which means it has further to reverse. it is this reverse time that is causing the Axis alarm to activate as it is talking too long to reverse and times out before the switch is reset.

If i reduce the Axis speed, then the homing slows down and does not over run the switch so much and thus has less distance to reverse and therefore has enough time to reset the switch, however, the jog speed is also slowed to a painfully slow speed.

Hope this makes sense.

Would i be better off with proximity switches rather than mechanical limit switches?

Thanks

Dean

 

[deanr181]

Hi Arie,

Just an update, It seems the reason I thought the jog and homing was going the same speed is that i was not changing the speed by much and was set about the same speed as the Homing. Sorry for my misunderstanding.

What i just tried was to double the speed to 15000mm/min and this jogs perfect now.

I think i have also fixed the back-off reverse speed. i increased the Acceleration setting and now doesn't over run as far and backs off in time.

Fingers crossed this continues to be okay.

thanks Again

Dean