K2633 Input Voltage

Kits PC Related Projects
1

Hi, I am using the K2633 to switch 24V solenoids. I am using an arduino microcontroller (MAX 5v @ 20mA per channel) as the input to the K2633. What voltage/signal is required by the K2633 to activate the relays on the board? The supply voltage I am using is a 9V supply hooked on VDC.

Thanks in Advance

2

The inputs of the card require open collector transistors. You cannot control this card from a 5V output of a microcontroller, as the inputs of the card are pulled up towards the +9V.
You will need to add 4 resistors and 4 NPN transistors to allow control from a microcontroller output.

3

So I would need to change the transistors on the K2633 to NPN transistors?

4

Please read my previous post carefully. Do not replace the K2633 transistors. You must ADD 4 external NPN transistors (e.g. BC547B) Connect their collectors to the inputs 1…4 of the card and connect their emitters to the GND of the card. Connect their base by means of a 10K resistor to the outputs of your µ-controller. Please seek local help if this information does not allow you to perform the necessary modifications.

5

Thanks for all your help. I can do that.

6

Hi, basically the addition of the NPN transistor & resistor just grounds the input pin correct? When its all said and done, the LED lights up but the relay does not activate. I know the relays work though, because if the collector and emitter on the PNP transistor are shorted, the relay activates.
Any help would be appreciated,

Thanks

7

Does the relay activate when input 1…4 is shorted to ground ?
If it does, then the 10K base resistor of the added transistors is probably too high. Try 1K

8

No, the relay does not activate when an input pin is shorted to ground. The LED does light up though.

9

Strange. Check the direction of the leds.
Furthermore, it cannot harm to increase R5…R8 to 1K
If necessary, replace all 4 transistors.

10

I’ve checked the polarity of the LED and replaced the transistors… nothing is still working. The relay activates if the Emitter and the collector are shorted together. Any help would be appreciated

11

Sorry, I’m afraid I have no clue as to what might be wrong.
This is such a simple circuit. Probably something very obvious is missing.
I can offer to check out your circuit. You can mail it to:

Velleman Kit Tech Dept.
Legen Heirweg 33
9890 Gavere
Belgium

12

I think we got it. The instructions say to make RX 820 ohms and R5-R8 82 ohms, but it should be the other way around. That and the combination of replacing all the PNP transistors got the circuit to work.