power supply percentage vs. mA

[swamidog]

i bought the "Quality 60W CO2 Sealed Laser Tube":

Power: 60W
Triggering Voltage: 25KV
Operating Voltage: 18KV
Current: 20~23mA

and the "80W PWM CO2 Laser Power Supply (110V)":

Input: AC 110V
Power: 80Watt, 100Watt peak
Triggering Voltage: 28KV
Operating Voltage: 22KV
Current: 28mA

Based on the ratings on the tube, I know that I should keep the current under 20mA.

I bought the 100mA analog current meter and have it wired in, but it's not clear to me how the Power% (what is the difference between min and max) in Lasercad and in the AWC608 correspond to tube current.

I keep an eye on the meter and I'm interested in not destroying my tube, but the analog meter is not very precise and it's hard to get a good reading with the needling jumping around.

What does the Power% number mean. Is it a linear scale corresponding to the output current of the PSU, or is it something more abstract.

If it's percentage of total output capacity of the PSU, then a max power of ~70% should be safe.

Is this correct?

Thank you!

-Christopher

[1n2]

I think you will find, that, when cutting the needle wont swing around wildly.

It would be extremely unlikely that you will "overdrive" the tube while engraving as the power is turning on and off (like a pulse width modulator or closer an AC current).

It is this on off action that any gauge would have displaying!..a frequency counter would show it of course but then that would be useless for displaying the cut reading as behaves as a dc current ie constantly on!
Hope that makes sense?.

John

[Tech_Marco]

To Chris:

You must set the Max power to lock the max current that allow to output from the laser power supply. To do this, use LaserCAd to draw a box like 200mmx200mm and set the cutting speed to 1mm/s and set the power (on the layer) to 99%. Then fire up the laser and observe the current displaying on the current meter. If it is over the tube can handle, then stop the machine and change the "Max_Power" under System Options . For example, if you got 25mA and the tube can only take 22mA max, then change the Max_power from whatever you have to 20% lower. Save it and hit "RESET" on the LCD control panel (MUST TO DO IT!) otherwise, it won't take the new setting. Do it again and again until you got current closed to the max current the tube allowed. After that set, no matter what power % you set under the layer power setup, it won't exceed the max current.


Marco

[swamidog]

thank you!

my machine is working great and i appreciate the assistance you've given me both in email and online.

To Chris:

You must set the Max power to lock the max current that allow to output from the laser power supply. To do this, use LaserCAd to draw a box like 200mmx200mm and set the cutting speed to 1mm/s and set the power (on the layer) to 99%. Then fire up the laser and observe the current displaying on the current meter. If it is over the tube can handle, then stop the machine and change the "Max_Power" under System Options . For example, if you got 25mA and the tube can only take 22mA max, then change the Max_power from whatever you have to 20% lower. Save it and hit "RESET" on the LCD control panel (MUST TO DO IT!) otherwise, it won't take the new setting. Do it again and again until you got current closed to the max current the tube allowed. After that set, no matter what power % you set under the layer power setup, it won't exceed the max current.


Marco