HDBB2 RJ45 Axis connectors - what current?

[LBayZG]

I would like to know the max current capacity of the RJ45 axis connectors on the HDBB2 board.
The relevant section of the HDBB2 user manual is 2.4. It does not give any information.

There is no other information than the pinout of the RJ45 connector.
1) What voltage of the Step and Dir signals?
2) What is the max current these lines can source or sink?
This is ambiguous, because the HDBB2 board is running on 12v and the UC400ETH is putting out 5v signals.

I need to know so that I can check compatibility with my M542 stepper driver. Do I need to build buffer circuits?
From the documentation, the M542 simply has an opto input, but I don't know if the axis signals can handle that.

[Robertspark]

Hello,

If you look at the PCB tracks within the manual (page 3/14) and follow them from the RJ45 connectors you will see that they are routed directly to the centronics connector (i.e. they are TTL, 5V input, and directly driven by your parrallel port or motion controller).

Hence the source and sink current will be the same as your motion controller ports and pins (normally ~20mA max), but I normally design on 10mA as that is whay the optoiolators will normally require on your stepper driver.

The M542 can be connected directly to the HDBB2 as it has optoisolators.

[note, I don't work for cncdrive and am just a passer by, but saw your post had not been answered]

[cncdrive]

Thank you Rob, you are absolutely right with your answer.
And sorry for no answer from me, I missed to see this post somehow.

The RJ45 step/dir pins are simply connect through the PCB, there is no inbetween electronics on the HDBB2 PCB for these, so the signals are just passed through.
This is why there is no mention of the current rating in the HDBB2 manual, because the max.current will be what the device can produce which device is connected to the HDBB2 and which produces the signals.
Mostly that is around +-20 to +-25mAmps if the device has standard TTL buffer chips.
The HDBB2 RJ45 pins will be sure not the bottleneck, because a pin like that can handle about 1Amps of current.

[LBayZG]

Thanks for the information.
Now I have reasonable confidence that I can tie the pins from my RJ45 (ethernet) cables directly to my m542 drivers.

[cncdrive]

Now I have reasonable confidence that I can tie the pins from my RJ45 (ethernet) cables directly to my m542 drivers.

Yes, sure you can. We did that countless of times in some of our installations.