MOD54415 / M12 Ethernet Conn

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DBrunermer
Posts: 67
Joined: Thu Apr 21, 2011 7:06 am
Location: Pittsburgh, PA

MOD54415 / M12 Ethernet Conn

Post by DBrunermer »

Hello,

I'm sorry if this is covered elsewhere. I read the App Note on using your own ethernet connector, and it made it clear we should reach out for help regardless of how well we think we know what we're doing. Which is good for me, because I'm not very confident and it gives me a fine excuse for looking stupid (not that I need one).My ultimate goal is to implement a 4-pin M12 d-pinout industrial ethernet connector instead of the RJ-45.

From the App Note:
Appnote1.PNG
Appnote1.PNG (126.61 KiB) Viewed 3828 times
My first question is about hooking up VCC. Is this schematic saying that VCC comes from J3 on pins 3 and 6 and should simply be connected to the CT of the magnetics, or is it saying I should add additional feeds to the NB thru J3 and also feed it into the magnetics CT? My second question is in the depiction. This is from the spec sheet for the Halo product:
HaloSpec.PNG
HaloSpec.PNG (20.73 KiB) Viewed 3828 times
I'm asking this because I want to make sure I use my magnetics properly. The app note seems to suggest that the configuration of the transformers on the RX and TX side are 'inverted', if you will, while the spec on the Halo suggests that the oriention of the transformer pairs stays the same on both the RX and the TX side. Do you understand what I mean? If you call them Vertical or Horizontal, the Halo product shows VH, VH for both the TX and RX, The App note shows VH on the TX side, HV on the RX side. Which is correct?

For magnetics, I choose a Wurth Elec product, #749020100, which has the exact same attenuation per frequency band as the Halo product. But it shows this internal schematic:
MAGS.PNG
MAGS.PNG (28.43 KiB) Viewed 3828 times
It clearly doesn't have the internal resistors the Halo products shows, or the connection to the capacitor. But by the same token, I'm using the 4 pin M12 shown in the next picture. Phoenix Contact 1411975. How should I terminate the CTs of the cable end? I don't have a J4,5, etc. Do I need to add the resistors and capacitor?
pheonix.PNG
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This is the best depiction of the cable end I could find:
EN_Pinout_M12-Dcode-20.gif
EN_Pinout_M12-Dcode-20.gif (9.11 KiB) Viewed 3828 times
This is the current schematic, not knowing exactly which was I should connect the magnetics:
enetschem1.PNG
enetschem1.PNG (13.98 KiB) Viewed 3828 times
I've clearly got a ways to go. Any advice or answers much appreciated.
Sincerely, Dan B.
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pbreed
Posts: 1080
Joined: Thu Apr 24, 2008 3:58 pm

Re: MOD54415 / M12 Ethernet Conn

Post by pbreed »

The center taps on the cable side, are probably ok to leave off....
Teh centertaps on the netBurner side do need to be connected.

The inversion should not matter as all modern PHY's have built in correction for this ...

And the VCC is sourced by the netburner you do not connect VCC there... (In fact on some boards the CT is not VCC and the "Vcc" pin does not go to VCC.) It depends on the Ethernet PHY.
DBrunermer
Posts: 67
Joined: Thu Apr 21, 2011 7:06 am
Location: Pittsburgh, PA

Re: MOD54415 / M12 Ethernet Conn

Post by DBrunermer »

pbreed - Thank you so much for the clear and concise explanation. But I'm sorry, if I could ask one follow up. Should I ground pin 7? - Dan B.

in case anyone is curious, that connector is not the right one for M12 Ind. Enet. You need something more like Conec #43-01223
DBrunermer
Posts: 67
Joined: Thu Apr 21, 2011 7:06 am
Location: Pittsburgh, PA

Re: MOD54415 / M12 Ethernet Conn

Post by DBrunermer »

Just in case anyone's following along, this totally works! I had the schematic wrong for M12-Ethernet. 1-3 is TX+/-, 2-4 is RX+/-. I used these parts:
1 - Magnetics - Abracon LLC # ALAN-101-T (Digikey 535-13501-1-ND)
2 - M12-4 D Conn - NorComp Inc # 861-D04-213R004 (Digikey NOR1818-ND)

Some schematic / layout snips
The NetBurner Connector
NB_Conn.PNG
NB_Conn.PNG (8.63 KiB) Viewed 3609 times
The Magnetics hookup
NB_Conn.PNG
NB_Conn.PNG (8.63 KiB) Viewed 3609 times
The M12 Connector
NB_Conn.PNG
NB_Conn.PNG (8.63 KiB) Viewed 3609 times
The relevant layout area
NB_Conn.PNG
NB_Conn.PNG (8.63 KiB) Viewed 3609 times
Thanks for the help, and I hope someone finds this useful in the future!
- Dan
Attachments
MagSch.PNG
MagSch.PNG (15.43 KiB) Viewed 3608 times
M12Sch.PNG
M12Sch.PNG (4.57 KiB) Viewed 3608 times
layout.PNG
layout.PNG (26.88 KiB) Viewed 3608 times
DBrunermer
Posts: 67
Joined: Thu Apr 21, 2011 7:06 am
Location: Pittsburgh, PA

Re: MOD54415 / M12 Ethernet Conn

Post by DBrunermer »

Don't know why the pictures came out wrong, but I think you get the idea. - Dan
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