Does the Velleman K8064 need a filtering capacitor with arduino PWM or not?

Other Hardware Motors, Mechanics, Power and CNC
1

OK, I'm trying to settle this issue here, once and for all. Also, I need to know which additional parts I should order.
If you know the answer, I IMPLORE you to reply, as googling throws up so many similar unanswered questions.

Here, massimo suggests using a capacitor.

Here, Magician says it's unneeded.

Can anyone lay this to rest please?

Thank you,

mm

2

megamasha:
OK, I'm trying to settle this issue here, once and for all. Also, I need to know which additional parts I should order.
If you know the answer, I IMPLORE you to reply, as googling throws up so many similar unanswered questions.

Here, massimo suggests using a capacitor.

Here, Magician says it's unneeded.

Can anyone lay this to rest please?

Thank you,

mm

Well my opinion matches Magician's. Looking at the schematic of the dimmer in it's owner's manual I see a low pass filter in the output stage of the opto-isolator. So adding further low pass filtering upstream probably won't buy you anything and therefore not required.

Lefty

3

So I should just be able to hook the pwm pin to the velleman board? (possibly through a resistor?)

4

megamasha:
So I should just be able to hook the pwm pin to the velleman board? (possibly through a resistor?)

I think so. The biggest deal will be setting up the variable pot adjustments (RV1 & RV2) per the instruction manual. They suggest that you use a 0 to +5vdc voltage source to set the values, so that implies you can use it with the arduino PWM signal which is 0 when 0% duty (0 count) and +5vdc when 100% duty (255 count). However the board is specified to use a 0-+10vdc control signal, so it's not clear that it will have a fully functional range at +5vdc max input signal, but then again I think the adjustment of the two pots adapts the board to the input signal range. Worst case the input circuit to the optoisolator has a series current limiting resistor (so you don't need to add one externally between it and your arduino PWM output pin) of 4.7K ohms, so if you were just add a another 4.7k ohm resistor wired across the existing one (R16) that should make the board optimized for 0-5vdc Vs the existing 0-10vdc rating. But again I would first just follow the adjustment steps using 0 and +5vdc to see if the dimmer works over it's full range.

Hope that helps.
http://www.vellemanusa.com/downloads/0/illustrated/illustrated_assembly_manual_k8064.pdf

Lefty