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Trying to get PWM to work

Added by teackele about 3 years ago

Hello all

I'm tuning and fiddling with laos lessercutter of a friend of mine (leenvw). Got a few issues solved but can't seem to get PWM to work.

What i have is:
HPC 3020
Laos Rev 3 Board (laoslaser-2015-03-18.bin firmware)
Juli 2012 Power supply (http://redmine.laoslaser.org/projects/laos/wiki/HPC_July_2012_power_supply)

What i have tried:
- connected 470 ohm resistor between P2.1 (5V) and P2.2 (IN/Setpoint).
- connected P2.2 to exhaust enable C
- connected P2.3 (Gnd) to exhaust enable E
- disconnected potmeter cable blue form P2.1 and Pot red cable from P2.2

Result:
Lasering only possible at one low power

Next:
Changed 470 ohm for 1k -> lasering at one slightly other power

Measured with scope over 470 ohm resistor during startup and lasering -> No PWM pulse
Measured with scope between Pin 22 of mbed and GND (while plugged in) -> No PWM pulse

What am I missing here? Shouldn't there be at least the PWM pulse on Pin 22 pf the mbed?

Regards Teackele


Replies (2)

[SOLVED] RE: Trying to get PWM to work - Added by teackele about 3 years ago

The output port of the mbed was broken. A new mbed solved the problem.

Teackele

RE: Trying to get PWM to work - Added by arjan about 3 years ago

I also tried to use PWM. After cutting the cables loose from the podmeter the board will not boot. There is current going to the axis, because I cant move them.

See video. Any idea what causes this?
https://goo.gl/photos/PBEDrcfRmgkNpKWP8

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