Duex fan8 port work weird

matej1006

Hello

i connect my small Dc Relay for controling led light in my printer. And when i send

M42 P7 S1

then voltage is 1.69V and when i send S0 then voltage is almost 5V
but when i connect my relay he won't switch, what can be wrong?

and this is my Config code for pin on Duex

;LED LIGHT SYSTEM
M950 P7 C"duex.fan8"

A Former User

@matej1006 said in Duex fan8 port work weird:

duex.fan8

maybe show us how its wired up, and where you put the diode (if not internal to the relay(module)?
(edit: seems diodes have been added to v0.8 and 0.9a boards)

Some voltage drop is expected, but 1.69v seems excessive.

matej1006

it's nothing big just one small 5Vdc relay connected directly to fan8 output
and then this relay control 12v DC led light

matej1006

when i change to Fan3 there work's normaly

matej1006

that is how connected:

T3P3Tony

and to confirm this same wiring works when connected to fan 3? which version of the Duex5?

T3P3Tony

There is no difference in the design between fan 3 and fan 8:

Please report the voltage measures on Fan 3- and fan8- with out the relay connected, relative to ground, both with the output set on (M42 P7 S1) and with it set off (M42 P7 S0). they try the relay connected, and test again.

matej1006

Yes same wiring on Fan3 works as should