brick PS

There is no 5V input on master brick

"Step-Down Power Supply brick" work only with 6-30V voltage.

In my project i use 5v supply, Can i connect my 5V PS in to "Step-Down Power Supply brick" 5v output to supply master brick without connecting 6-30V in ??

There is a 5V input for the Master Brick. It's the mini USB connector on the brick.

Use an USB cable, cut one end and use the red (+) and black (-) cables to connect to your 5V power source.

Step-down needs 6V at least.

But the question is: Can I put 5v from external PS into "Step-Down Power Supply brick" OUTPUT without providing anything to INPUT and power other stacked bricks in this way?

The problem is that i don't want to power it via usb.

Maybe I completely miss what you really want, but...

Can I put 5v from external PS into "Step-Down Power Supply brick" OUTPUT

No, as the name OUTPUT already indicates, it's an OUTput.

An your other statement

There is no 5V input on master brick

is wrong. As I said you can run the master brick without any Step-Down Power Supply! Use the mini USB connector on the master brick for supplying it with 5V.

I know that output is for output purposes but! i want to know if it can be used as input to power up whole bricks stack.

I want to use "Step-Down Power Supply brick" only as 5v connector.

Maybe it is more clear now what i want to achive.

No, as raphael_vogel already mentioned, you can't use the step-down for 5V input (green jack). This would also be a quite expensive solution: why buy a step-down and supply this with 5V if you can do the same without step-down?

You can supply one brick with 5V via USB connector (see remark from raphael_vogel) which powers the whole stack then, not just that one brick.

Actually, with the currently available Step Down Power-Supply you can attach a 5V supply to the green connector, as long as you connect nothing to the black connector.

Since we want to protect the stack against accidentally connecting to the wrong connector in the future, this will not be possible in the next version of the Step Down Power-Supply.

(Accidentally killing a whole stack because you connect 24V to the green connector instead of the black is currently one of the most painful things that can happen )

Thank you.