Z axis soft limits

[Greolt]

I am starting a new thread for this topic so as to hopefully keep it clear.

This first post is some background for any interested readers.

A lot of AWC608 users who have a motorised table or Z axis do not have a limit switch and therefore do not have the Z axis (table) set to, "Z axis home onPower".

The Z axis (table) is simply lowered or raised to adjust the focus height for a given material. Or in my case, sometimes lowered way down to fit the rotary axis.

At present whenever the AWC608 is started up the Z axis is set to zero by default and the Z axis (table) can only be raised, not lowered. It is already at zero.

This turns out to be a real nuisance.

Some work arounds are;

1. Go through the process of a manual Z axis reset. (time consuming)

2. Lower the Z axis (table) to the lowest position before shut down. (I never remember)

3. Use U axis control for the Z and select " U axis for feeding" (this is what I have been doing, not ideal but it does work)

Greolt

[Greolt]

I made request to Marco to see if we could get an option to disable the soft limits on the Z axis.

It is worth noting that the U axis soft limits are disabled when "U axis for feeding" is checked. If it can be done for U axis, it is likely to be a simple matter to do the same with Z axis.

The programmer was working on a few new updates and I hoped this might be good time for this request.

Marco has been good enough to respond positively and sent this message.

Just received a new OS update with the capability to disable the softw limit switch for the Z.
But I'm not sure if it work the way you're expecting. Li said that if you disable the soft limit for Z, then you need to add a hardware limit switch instead.
I'm not sure what is that as I never use Z table.

I let you try it. What is your current OS version? I'll send you a file to upgrade it and you can try it

Marco

Marco then sent me links for the latest LaserCAD version 6.46 and firmware including alterations to Z axis soft limits.

I have now been able to test the upgrade and this is my results so far.

Previously upon startup the Z axis would be set by default to zero at the position the axis was presently in. (no Z axis limit switch and no "Z axis home onPower")

With the latest LaserCAD and firmware I can find no setting to disable the Z axis soft limits. Either in LaserCAD or the LCD panel control. I guess with this being just a test version, that this was not as yet included.

What I have found to be the difference to previous version is as follows;

The Z axis is set at start up, by default, to middle of the Z axis "Range" as set in "Other Axis Parameters"

So if Z axis range is 50mm then at startup, position will default to 25mm. If range is set to 300mm, then at startup, position will default to 150mm. Etc.

This is in practical terms an improvement but not really what I was hoping for.

I hope I have explained adequately what it is I am requesting. Basically in simplest terms, a setting to disable or ignore soft limits on Z axis. As is already available for U axis.

Thanks for your attention and efforts in this Marco.

Greolt

[Telrad]

I guess you will have to set the z axis range for twice the actual size so you wont run into the new soft stop point. It's too bad the laser cant retain the z axis position between resets.

[Tech_Marco]

Just hand in there. Let me setup a Z table by using a small XY stage as I don't have a Z table by now. I will do some simulation so I will understand what is an issue here. There must be a solution.

Marco

[Tech_Marco]

I have talked to Li and he told me that the current "Auto focus" mechanicism was and ideao from previous card. I discussed with him about the problem you guys are having and made a suggestion (man, took me 2 hrs to explain) to him 'how to' make it better. Finally he agred my point and he is going to re-design the mechanism of 'auto focus'

Here is my suggestions:

1) Eliminate the necessary of drivng the Z table to the bottom and move up. Time wasting
2) Eliminate the use of lower limit switch Z- as the 'Range' works as a software limit
3) Allow freely moving the Z up and Down after 'auto focus'

Once the change is completed, the auto focus should work much better and faster. It should just take a fraction of previous model say 4~5 seconds should take care previous 20~30s work

Folks, you got really need to treat me well, a beer would be fine or a glass or red wine . I been spending so much time and effort to pursuade him to take the big step to make the change.


Marco

[Telrad]

Why not remove the z range all together and just rely on the hardware limit switches to stop the table?

[Tech_Marco]

I don't see there is a necessary to install 2nd hardware limit switche but not using a 'software limit switch'. For a second hardware limit switch, first of all, you need to add a physical switch to the stages, then you need to come up another pair of wire. So, why not software?

The issue is not the 'range' but the capability of movine the Z up and dn. That's why you guys want the most. Before, you can move up only means that you can't load smaller object (less height) but bigger object. Now, with the capability to move up/dn, that is no longer a problem. Agreed?


Marco

[Telrad]

I agree. I had both the z+ and z- switches already installed before I switched to the awc608. The z+ switch was nice It seems easier to me to program the software to just disable the z soft limits. Both systems would work.

Thanks for your time spent on this nigling issue.

[Greolt]

Here is my suggestions:

1) Eliminate the necessary of drivng the Z table to the bottom and move up. Time wasting
2) Eliminate the use of lower limit switch Z- as the 'Range' works as a software limit
3) Allow freely moving the Z up and Down after 'auto focus'

Very much appreciate your efforts on this Marco.

However all I was suggesting was a check box to disable Z axis soft limits. As is the case already with U axis.

I don't use auto focus. Just do it manually.

Thanks again.

Greolt

[Tech_Marco]

Greolt:

Can't just simply add a button to disable the 'Z' as this channel is designated for 'auto focus'. There is no easy task and I have explained to you guys that the programmer would re-write the whole mechanisms for auto focus 'Z'. Sometimes we see things differently vs. the programmer. You may think it's stupid but there is a reason behind the case you and me don't know.

As I mentioned, I've spent a whole hour to make him to understand the necessary of being able to disable the 'soft Z'. He took my idea and he said that a new OS should be ready in a few days. He is working on it.


Marco

[Greolt]

He took my idea and he said that a new OS should be ready in a few days. He is working on it.

That's great Marco.

Look forward to the results.

Greolt

[Tech_Marco]

Now is 11:00pm (PST). The China time is 2:00pm. Per Li (programmer), 15 more mini and he will come up a new patch! I'm waiting ......

Marco

[Tech_Marco]

Got the modified "Z auto focus" OS at 11:40pm. 10min late from Li

Marco

[Telrad]

Could I try it out for next week? Im running the latest firmware and laserCad you have released V6.27.

[Tech_Marco]

I think there is a 'bug' in the new patch. The idea how it handle Z auto focus with cable to move Z up and down seems in the right path. But I think Li did it in rush and forgot something. When hitting 'Auto focus', the Z won't move and LCD was showing "Auto focus....". There was no action when I triggered the Home limit switch.

But, if I hit Reset button on the LCD control panel, then the system reset and Auto focus seems working. Note, the range on Z to travel is determined by Range of Z and there is no hardwae limit switch to protect it. So, make sure that this range is within the Z value and no beyond or it will crash to the side. Also, you need to use LCD to set the 'Z origin' it's a distance the laser head will travel revesed once it hit the Z home switch (sensor probe). Default is "0" mean that when Z is home and it will stay at Home (0) with sensor latched. But, we need the Z to back off a couple "mm" to release sensor probe from the latch and that is the distance you need to find out for the focus point.

Anyway, I'll ask him to fix the little issue.

Marco