Trying to work out what optocoupler to get, the circuit design is the atmega 2560 and uses 7 pwm pins to feed high power led drivers, one arduino output has been fried my own fault for shorting the pwm feed to ground so looking to get an optocoupler to isolate its from the led drivers, the pwm is 0-255 so will need the same at the other side of the optocoupler, will any do or do i need a high speed one something like the 6n137
cheers in advance
kev
the pwm is 0-255 so will need the same at the other side of the optocoupler,
What exactly does this mean?
PWM from diffrent pins operate at diffrent frequencies so check the info on this site to see what you have, but generally yes you need a high speed opto.
Sorry Mike on the sketch on the arduino 0 been off 255 been on 100% thats how many steps the led ramping has the pwm frequency has not been altered so would think that is as std if thats how it works sorry still quite new to it all, saw this on frequencies on another thread, 980Hz on 5 and 6, 490Hz on 3, 9, 10, 1
I am using
//Define the PWM PINS for the LEDs
const int ledPinSump = 7;
const int ledPinBlue = 8;
const int ledPinWhite = 9;
const int ledPinRoyBlue = 10;
const int ledPinRed = 11;
const int ledPinUV = 12;
const int ledPinMoon = 13;
But that has nothing to do with an opto isolator. It is the basic PWM frequency that you need to know.
Is that the basic pww freq from the led drivers side, the arduino or the optocoupler/isolator ?
sorry for all the questions
And just another on leds whilst i am on,
got a 36v 11amp psu turned down to 33v runnig 5 x 50w leds.
the leds specs are DC Forward Voltage (VF): 30~34Vdc. DC Forward Current (IF): 1500mA
The pwm driver is max current of 1200ma at 31.7v feeding the led, iS there any protection i can use on the led in case the driver fails at £50 a pop not cheap leds, simple fuse or resistor ?
Is that the basic pww freq from the led drivers side, the arduino or the optocoupler/isolator ?
The basic frequency that the arduino puts out, the opto has to be able to cope with an response time of 1/( PWM frequency *256 * 3 ) seconds at least.
DC Forward Current (IF): 1500mA
The pwm driver is max current of 1200ma at 31.7v feeding the led,
So there is no way you can use that driver with that LED.
Sorry have to disagree about the driver it is set up running as we speak, will try to find a fast optocoupler
regards
kev
Not my led but same kind of set up
http://www.ebay.co.uk/itm/High-Power-50W-White-LED-Driver-Heat-Sink-/380531424736?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item589970bde0
Sorry have to disagree about the driver it is set up running as we speak
If the driver can only switch 1.2A and the load you are switching is 1.5A you are by definition overloading the driver. Specifications are published for a reason. Sure it might not have blown up yet, but at some time it will. Or do you not care how long it lasts?
No wonder they call you Grumpy Mike great name !
How can a led driver be overloaded when they are designed to regulate current, all leds in aquarium builds are not run at the full amount like the xte crees capable of 1.5 amp yet most run at 1100ma or 1200ma using a 1200ma driver so whats the difference, If a led driver did provide more then the leds can handle then the leds would simply burn out, And yes i do care how long they last HENCE leds been under driven derrrr