Generall question from an absolute rookie

Hey everyone,

first of all: I’m really absolutely a rookie and have very limited knowledge about electronic hardware.

I'm sorry, if my question is on the wrong board or if it’s simply stupid.

To my problem:

Currently I’m using this mosfet board:

To insulate my USB-Port / PC from the output 24V DC current.

My question here is: Is this the most safest/best solution for what i am doing or can i select another, safer circuit for my application?

For more details about my application i try to summarize the most important facts:

Via USB and a NI 6001 DAQ i can generate a 2,4 ~ 5 Volt signal to switch currently a mosfet board, switching the output site to a 24V DC current with 500 mA output at each channel (8 channels in total, summing up to 96 W)

The danger in the system is, that due to heating wires on the output site a 230 V short circuit could happen, and thus a save isolation between PC and output site has to be granted.

As I'm a total rookie in that field, i don't even know which keywords i have to look up to tackle my question^^

So, thank you in advance for your help and comments.

Best,

Rene

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Can you post a diagram of how you are connecting everything.
Please include the 230Vac that you have doubts about, in your circuit please.

I understand you have a DtoA converter controlled by your PC.
You want the DtoA to provide 5V to the optically coupled PCB.
This isolates the 5V from the 24V you are switching at the output.

That PCB will do the job.
PCB Schematic.
optofet.jpg

Tom… :slight_smile:
Can you please tell us your electronics, programming, Arduino, hardware experience?

Noone mentioned DACs, this is a data acquisition module, basically an I/O breakout for USB.

For simple on-off an opto-isolated MOSFET switch like this is going to work well. If you want
PWM control however, opto-isolation is not likely to work as its too slow (with most common
isolators).

Make sure you have complete galvanic isolation - some of the opto boards allow the option of sharing
power with the input (which completely negates the purpose of isolation), so check its configured
so that there is isolation (check with multimeter).

For mains isolation you'd want also the check the physical separation on the PCB is adequate, at
least 5mm, preferrably somewhat more with slots in the board under the opto units.

MarkT:
Noone mentioned DACs, this is a data acquisition module, basically an I/O breakout for USB.

daq.jpg

Tom… :slight_smile: