forum.cncdrive.com

Is it ok to use the 5v output on the UCBB1 board to power a UC300ETH?



Thank you,

Dennis

Other way around, actually. From the UCBB documentation:

"When using a motion controller like the UC300ETH-5LPT then the UCBB board gets this 5Volts
power from the motion controller via the 26.pin of the IDC connectors."

I did see that, but was thinking if one 24v power supply is used and the 5v out from UCBB1 can power uc300 will make a cleaner setup.

A step down regulator can be used also. But still would like to know from electrical perspective if bb can power uc300.

If you use the same power supply then there will be no isolation between the UC300 and the inputs/outputs.

From manual:
3.4 Outputs
There is a total of 16 optically isolated outputs on the UCBB board.
All outputs are electrically identical and all of them using high speed 10Mbits/sec optocouplers and
an N-channel power Mosfet with 50Volts voltage and 2Ampers current rating.

3.5 Inputs
There is a total of 18 optically isolated inputs on the UCBB board.
All inputs are electrically identical and all of them are using high speed 10Mbits/sec optocouplers.
The inputs were designed to work within the 12V to 24V input voltage range with the 2.2kOhms
onboard resistors in series with each input.

Looks all I/O's are opto isolated.

The 5V output from on the UCBB is referenced to the same 0V as the 24V power supply input. This can be known because both return sides are marked 5V0.
So, if you will power the UC300ETH-5LPT with this 5Volts then you will use the same power supply for both the 5V and the 24V side which is a problem because you will bypass the isolation of the UCBB.

The 5Volts power is used to power the digital part, the UC300ETH side. The 24V is used to power the external side, the outputs abd inputs after the optical isolation. This side is where your relays, sensors and switches on your machine are connected. This two sides should be isolated from eachother, they should not share a common 0 Volts, so is why 2 separate powersupply should be used.

Thank you for the explanation, got it now, was looking at it from wrong angle...

cncdrive wrote:The 5V output from on the UCBB is referenced to the same 0V as the 24V power supply input. This can be known because both return sides are marked 5V0.
So, if you will power the UC300ETH-5LPT with this 5Volts then you will use the same power supply for both the 5V and the 24V side which is a problem because you will bypass the isolation of the UCBB.

The 5Volts power is used to power the digital part, the UC300ETH side. The 24V is used to power the external side, the outputs abd inputs after the optical isolation. This side is where your relays, sensors and switches on your machine are connected. This two sides should be isolated from eachother, they should not share a common 0 Volts, so is why 2 separate powersupply should be used.

Sorry to drag up a old thread but IF I have a 24v and a 5V power supply I find that both are earthed together anyway thought the power supplies Gnd and the 240 Gnd ? so they all share common 0 Volts -I am missing something here on how to isolate the two volages gnd from each other.

Or do I break code and not connect the GND wire on the 240V system ?

There are only 2 rules:

- Always connect PE.
- Don't use power supplies which have any of the outputs connected to PE.