Z Table & AWC-708 Newbie Questions

[Dean315]

Hi Guys, I have a K40 that I've successfully upgraded to the 708 and one of LO's powered Z Tables. I originally ordered the table thinking I'd cobble together a circuit and use a couple of push buttons but obviously discovered that the DSP already has that covered. Now I'm wondering what else the 708 can do in relation to the Z Axis. I'd love it if it would display table height. Even better would be if I could tell the DSP to move it to a certain height. Better still would be if I could include that info in the job file so I could automatically defocus then refocus as needed during the job. Is any of this possible? If so, how do I do it? Without a good manual on the various DSP boards, it's hard to tell if something is doable, let alone how to do it.

Z-Axis limit switches: Right now I only have one at the bottom of travel on the table it doesn't seem to do anything. When I move the table down it hits the switch and keeps going. I have it connected the same way as the X and Y switches, GND and Z- if memory serves, and polarity set to negative. I've tried various combinations of settings with no luck. Any suggestions? Also the DSP only has connections for one Z-Axis limit. How does one implement both upper and lower limits? If you just paralleled them the DSP would not know which way to move in order to get off the limit.

Thanks,
Dean

[Techgraphix]

In fact, you don't need Z-limitswitches at all.. When you use the autofocus, where you trigger the autofocus-sensor there is your zero-point. Any offset from that point (like when your actual focuspoint is a bit off the triggerpoint) can be set in the software.
So you just let your table rest somewhere, don't include it in the reset. Place your material and autofocus..
To get a real good autofocus I used a proximity-sensor just aside the laserhead, place a metal block of a fixed height on the material, just under the sensor. Push autofocus and the table is lifted till it triggers..
I have two Z-limit-sensors installed but really never used them.. It's also quite time-consuming to have your lowered to the bottom and move it all the way up again to where you can start the job..
Changing the focusdistance in a job can only be done by splitting the job and set the focus separate. In my case I would use a different autofocus block or lay something under it..

BTW my X7 DOES have connections for both ElZ- and ElZ+ (and ElU+ and ElU-)

Kees

[Dean315]

Thanks Kees! Unfortunately I'm not using auto focus. I hope to eventually but thought I'd better master the basics before attempting the "frosting on the cake" stuff. I'm thinking there has to be more Z-Axis capabilities in the X7 than just the manual push buttons or auto focus. Since there is a u/pulse calibration factor, that implies the ability to know, and hopefully display, the table height. Otherwise why would you need the distance per pulse calibration? Tell me a little more, if you don't mind, about your autofocus procedure. I saw another post where you listed some part numbers for sensors and I'm thinking that you mentioned that they only detect metal. Is that correct? If that's the case it seems to me that you would need a metal "calibration target" the same thickness as each piece of material you're going to etch or cut. I'm suspect I'm missing something. I have considered mounting some kind of switch, probably a micro switch, to a small stand such that I could sit on top of my material and the switch would be activated by some part of the laser head when the focus distance is reached. At that point I would remove the switch and stand and proceed with the job. Suggestions, ideas, or comments?

I did notice both the ElZ- and ElZ+ connections but I thought they were for limit switches that grounded the input versus connecting the input to V+. In other word, different connection options for the same switch rather than an upper (+) AND lower (-) switch. Thanks for educating me! I REALLY, REALLY wish there was documentation that went into this kind of detail. Do you know if the Z limits are supposed to stop table movement when they have been reached using the keypad up/down buttons? I would think that when pressing the down arrow, movement should stop, even though the button was still depressed, when the down limit was tripped but that isn't happening on my system. If I'm correct and the X7 is capable of measuring/displaying the table height it's going to need at least one limit/home home switch to know when the table is at "zero".

Maybe you can help with another problem? My X-Axis is moving in the opposite direction than it should and the "Key Direction" setting has no effect. The "Datum Direction" setting effects the homing direction as it should. The "Tracking" display on the X7 shows the proper direction. I had this problem when first installing the X7 and after a couple of weeks of frustration trying to fix it it started to work properly and I don't know what I did. Well today I rebooted the computer and the problem is back. It doesn't matter whether I set the "Key Direction" from the computer or the X7 keypad, nothing changes. I have used the password 608 to save the settings in LaserCad as well as the stop/shift key combo on the keypad. Any suggestions? Thanks for your help and comments, it's really appreciated!

Marco, feel free to jump in any time!

Dean

[Techgraphix]

A few things to set straight:
U is for feeding.. If you have a transport-system, you can program to do the job a number of times. after each individual job, the U travels a given distance to get a new, fresh, piece of material under the laserhead.
As probably only 1% has such a transportation in his laser, almost nobody can make use of the U-axis.. I attached some extra electronics to us the U-axis as an extra table lift when I want to multi-pass on thick material, so after each pass, my focuspoint lays a few mm deeper in the material.. It might not be the best methode to cut thick material, but it works..
For autofocus: I use a proximity sensor which I mounted on a bracket just on the right side of the head. With a steel calibration tool (nothing more than a U-shaped piece of profile) which I place on top of the material just under the sensor. Press autofocus and the table lifts till the sensor is triggered. That's it..
The sensorheight has to be calibrated only once (the first time). For that I made a ramp from +5 to -5mm and check for the thinnest part of the line.. If that is -2.5 for instance, I know my sensor is set 2.5mm too high. I can lower my sensor or enter that value in the software..
I know I also had this problem with key direction and moving when I first builded my laser.. I had a DF212 controller then, so it is of all controller types.
It took me a while to sort this out. Changing the direction can also be done with swapping the two wires of only on coil of the steppermotor (A+<>A- or B+<>B-)
I think I did that too.. and then set all the directions, starting with the move..
After that, this is my third controller and just took over the settings from the former one without problems..
It's a matter of trial and error..

I also noticed that a few settings made in LaserCad are NOT taken over in the X7 correctly.. I told Marco already..
You can check and set the values directly in the controller.. Press and hold STOP, then press SHIFT (in case of X7). this will enter the manufacturers settings page..(as you apparently know already)
See if all settings made in LaserCAD are the same as what you see on the controller.. Adapt the values in the controller if necessary.. After a reset it should work..

Kees