K8055 info!

Kits PC Related Projects
1

hi ,

i have a project , i used K8055 (In & Out)

but have some issues

in Digital Output : sometime when i turn a device ON the card gets disconnected and LED8 flashing i think theres a problem about connection

i didn’t use CLAMP port can i use it to solve this problem ???

also in digital inputs some times i get flashing on off on off even if the device has on all the time i used a relay when the device is on the relay with its connection will connects GND to any Digital Input then i get the input Value 0 or 1 its fine but sometime it keeps on off on off even if the relay on all the times

i connected outputs directly to drive relays with external power supply 12VDC (0-7)
i connected inputs with outputs of relays to GND of the k8055 with input Port (0-5)

Thanks in advance

Think

2

To protect the output transistors of the board and to avoid transients that may disturb the operation of the card, it is good to connect the positive end of the relay coil to the CLAMP terminal.
See the drawing on page 22 of the manual.

3

Thanks but i need to ask you

i am using my project in my car ,

and i used 4 cards of K8055

all relays are connected directly to my cards using GND and positive goes directly to the relay coil

my question is : Do i connect the Clamp to cars’s battery positive line ?

and what if i put diode to each relay is it better than CLAMP ?

Thanks

4

I think there is no difference using separate diodes or connecting the battery plus to the CLAMP terminal. The internal clamping diodes can handle current up to 500mA only.

You may read more by following this link:
maxim-ic.com/appnotes.cfm/an_pk/4240