co2 laser limit setup

[Tech_Marco]

It's not supposed to do it after I talking to a tech in China. Our partner sold over 300 boards a month to supply laser manufacturers in China and non of board need to add the 1K pullup resistor at the Limit terminals. As I mentioned before, if you see a dim led while, chance that you may have noise problem. The noise can be caused by a poor switching power supply or bad grounding. The leaking on a CO2 Power supply affect the most. FYI, I have three machine here and none of those need a resistor to work with switch. But it may not be bad to add your methode as a solution for similiar case. I'm learning everyday, and there are always new thing to learn.

Marco

[twehr]

It's not supposed to do it after I talking to a tech in China. Our partner sold over 300 boards a month to supply laser manufacturers in China and non of board need to add the 1K pullup resistor at the Limit terminals. As I mentioned before, if you see a dim led while, chance that you may have noise problem. The noise can be caused by a poor switching power supply or bad grounding. The leaking on a CO2 Power supply affect the most. FYI, I have three machine here and none of those need a resistor to work with switch. But it may not be bad to add your methode as a solution for similiar case. I'm learning everyday, and there are always new thing to learn.

Marco

Marco,

His problem was the lack of any signal voltage going through the limit switch. He was just trying to make/break ground. That did not do it. The 5v I suggested would have worked just fine by itself. I suspect the resistors he used simply adjusted the 5v down to 3.3v, which may also work.

NOTE: This may NOT be accurate. Officially, the system calls for ground via a NO switch. But when there is noise on the system, it may be that tying the signal high until contact is made with the switch, gets you get a cleaner operation. I will continue to investigate and provide details.

[Tech_Marco]

I talked to the tech and he said that the Limit control is not +5V activiated. It's Ground (0V) activiated instead. All Limit switches should be in common ground and the other pin of the limist switch need to connect to the #2 for Y and #4 for X. The reason I see that adding a pull-up resistor by all mean is to stay out the tri-state or the the input of #2 and #4 is always high so that it won't trigger the 'stop' signal to shop the motor from running. As I mentioned, there may be other issue and nois is what I concerned the most.

All the card has been tested on a mchine before shipping. I really see no reason why it won't work as it should. I been their facility and saw a tech there did all kind of tests on each card on a engraving machine. He setup each card to the machine, ran the software and let it engraved something with different speed. HOME is of couse the basic test. Until all result pass, then had it packed for shipment.

Anyway, everything could be possible. Hope no more probelm from his card, let's double fingers

[twehr]

I talked to the tech and he said that the Limit control is not +5V activiated. It's Ground (0V) activiated instead. All Limit switches should be in common ground and the other pin of the limist switch need to connect to the #2 for Y and #4 for X. The reason I see that adding a pull-up resistor by all mean is to stay out the tri-state or the the input of #2 and #4 is always high so that it won't trigger the 'stop' signal to shop the motor from running. As I mentioned, there may be other issue and nois is what I concerned the most.

All the card has been tested on a mchine before shipping. I really see no reason why it won't work as it should. I been their facility and saw a tech there did all kind of tests on each card on a engraving machine. He setup each card to the machine, ran the software and let it engraved something with different speed. HOME is of couse the basic test. Until all result pass, then had it packed for shipment.

Anyway, everything could be possible. Hope no more probelm from his card, let's double fingers

I could be wrong (it happens), but on my machine I use optical interrupt switches. It holds the signal high until the interrupt, at which point it allows the signal to go low. Works perfectly. That is why I suggested the 5v via a NC switch - when contacted it would open and drop the signal. That would be like what your tech is saying - activate on low (ground).

I'll have to check when I get to the shop to see for sure exactly how it is working for me.

[Tech_Marco]

Tim, your should works fine as I can tell. If laser is not home, I bet that there is pullup 5v sending from the optical switch that keep the Limit Input "High" and so no home signal sent to the card. But once it hit home, then an active low (0v) appear on the limit switch and cause the Input "Low" (0v) and trigger the home signal. It's totally making sense.

I have been thinking for days about what could it cause motor not being stopped at 'Home'. Well, back to my old theory. The only way to not allowing home signal generated is to have #2 and #4 High (5V) all the time. It's not necessary 5V, even 3.3V or 3.5V should be high enough to disable it.

Now I figured out a simple way to determined whether the cable is suspious to the noise or not. The best way to test it is to detached the cable from the Limit Input terminals and simply use a jump cable, or metal clip to short #2 or #4 to the ground to simulate the close contact action. If it the motor response and stop, that means something wrong with the cable and the sensor switch. But if it's not, it means the noise is coming from something else and the 1K pullup resistor is a good solution. Agreed?

[twehr]

Tim, your should works fine as I can tell. If laser is not home, I bet that there is pullup 5v sending from the optical switch that keep the Limit Input "High" and so no home signal sent to the card. But once it hit home, then an active low (0v) appear on the limit switch and cause the Input "Low" (0v) and trigger the home signal. It's totally making sense.

I have been thinking for days about what could it cause motor not being stopped at 'Home'. Well, back to my old theory. The only way to not allowing home signal generated is to have #2 and #4 High (5V) all the time. It's not necessary 5V, even 3.3V or 3.5V should be high enough to disable it.

Now I figured out a simple way to determined whether the cable is suspious to the noise or not. The best way to test it is to detached the cable from the Limit Input terminals and simply use a jump cable, or metal clip to short #2 or #4 to the ground to simulate the close contact action. If it the motor response and stop, that means something wrong with the cable and the sensor switch. But if it's not, it means the noise is coming from something else and the 1K pullup resistor is a good solution. Agreed?

Makes sense to me. I'll play with it a bit more this weekend.

You are right about why my works. The optical switch is holding it high. Then taking it low when interrupted. That is why I suggested he use 5v with a NC switch. That would drop out the v on contact. BUT, it might not take it low enough for the system to pick it up. That is what I want to test.

[baccus61]

Hi guys,
this is an interesting problem.
I usually use NC micro switches on all my home or limits as it's a bit more fail safe due to a wire breakage or simple faults like a dirty contacts etc.

It seems like it is in the wiring or switch. Have the switches all got the same problem or just one of them.?
Have the switches been swapped around to see if the problem still exists.

I found that the limits set up on the DSP board was definitely the hardest part of setting up the board and software as there are so many different ways you can do it. Very frustrating when you don't know what you are doing. The V2.0 board is much better as it has the STOP button on the front panel if you need to stop the homing process if one of the axis are going the wrong way. VERY helpful.

Rich.

[concretevapor]

another interesting problem...

already tried several wiring iterations, none of which that halted the X,Y movements upon limit switch triggering.

so i thought perhaps the switches were faulty, but then noticed the LEDs inside the controller were being triggered when I triggered the switches manually.

i decided to unplug the switches and bridge according switch ports on the controller, the LEDs were triggered but X,Y movement was not affected at all. did dont halt the motors, later i found out that bridging would not fix this issue since the motor will back up in order to release the switch.

i went over the DSP setup guide to reverse polarity as the switches acted reversed. (LEDs on the controller would turn off when according limit switch is triggered) although i did it by the book, saving the setting with the provided password... the problem remains.

could this be a faulty controller?

thanks

[Tech_Marco]

How did you connect the motor driver?
The chance to have a faulty XY limit switch is almost "zero" as all our controller tested one by one by the manufacturing. Usually the problem is either wrong connection or faulty device of other components.

Marco

[waltfl]

Hi there
check your end switches if they working probably I just had it with another customer anly after he took out the switch and replaced it it worked . thats probably happen in the beginning befor adjusting and setting all parameters and as the machine was banging against the endswitches. the controler some how shows the switches working when manualy activated but it is not true.
it has nothing to do with the DSP.
the next point is the OS upgrade without the right OS upgrade there is some problemes too and at all first set the paraneters in manufacturer and user settings right.
if you want a working manufacturer and user setting file just send me a PM to a542002@hotmail.com
greetings
waltfl

another interesting problem...

already tried several wiring iterations, none of which that halted the X,Y movements upon limit switch triggering.

so i thought perhaps the switches were faulty, but then noticed the LEDs inside the controller were being triggered when I triggered the switches manually.

i decided to unplug the switches and bridge according switch ports on the controller, the LEDs were triggered but X,Y movement was not affected at all. did dont halt the motors, later i found out that bridging would not fix this issue since the motor will back up in order to release the switch.

i went over the DSP setup guide to reverse polarity as the switches acted reversed. (LEDs on the controller would turn off when according limit switch is triggered) although i did it by the book, saving the setting with the provided password... the problem remains.

could this be a faulty controller?

thanks

[concretevapor]

How did you connect the motor driver?
Marco

TB6560 to AWC 608
pul- to pul(2)
pul+ and dir+ bridged to DC5V(1)
dir- to dir(3)

TB6560 to stepper motors
B+ blue
B- red
A+ yellow
A- white

both drivers have PINS 3+4 switched on

[concretevapor]

Hi there

just send me a PM to a542002@hotmail.com
greetings
waltfl

pm sent, thank you for your offer