DMX / Ren Pinouts from ECG.

Discussion in 'EthConGateway by Joshua 1 Systems' started by lytnin, Sep 21, 2010.

  1. lytnin

    lytnin Apprentice Elf

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    Hi All,
    I've got my ECG all built and the onboard LED's are flashing when I send it a test sequence.

    The time has come to connect up some controllers and get some real blinky flashy happening, but I can't seem to find any pinouts, or decipher the schematic.

    Can someone enlighten me (and others I'm sure) as to the Pinouts from the ECG slave to the DMX and also to Renard. (Pics would be great)

    Cheers
    Dave
     
  2. mschell

    mschell Full Time Elf

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    I believe that if you set the jumpers on the ECG-DMXRen8 for DMX, you'll get signal out on pins 1 and 2 of the RJ45. If you set the jumpers to the REN setting, the signal comes out on pins 4 and 5.

    Now, which signal (D+ and D-) is on which pin I can't remember. However, you can run a straight RJ45 cable from the ECG slave output to a Ren controller or RPM DMX controller and it will work. In fact, I had the Ren DMX firmware loaded on my Ren48LSD controller - told the ECG to send DMX, but had the jumpers on the Slave for Ren, and it all worked correctly.

    I believe the Ed (j1sys) posted jumper configurations in his DMXRen8 assembly guide.
     
  3. j1sys

    j1sys There are no rules, and those are the rules. Community Project Designer

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    I need to document. But the reason I hadn't is that the board is set by the jumpers to do either:

    The Renard RJ45 standard:

    Renard Controller RJ45 inputs (and daisy-chain outputs):
    Pin 1 - Ground
    Pin 2 - Ground
    Pin 3 - alternate zero-cross input (not connected)
    Pin 4 - Data-
    Pin 5 - Data+
    Pin 6 - no connection
    Pin 7 - Power input (not connected)
    Pin 8 - Power input (not connected)


    The DMX RJ45 standard:

    DMX Controller RJ45 Inputs (per ESTA):
    Pin 1 - Data1+
    Pin 2 - Data1-
    Pin 3 - Data2+ (not connected)
    Pin 4 - no connection
    Pin 5 - no connection
    Pin 6 - Data2- (not connected)
    Pin 7 - Link Common for Data1 (both connected to GND by default)
    Pin 8 - Link Common for Data2 (both connected to GND by default)

    So the reason I didn't document it yet is because they meet the standard which is documented elsewhere.

    -Ed
     
  4. lytnin

    lytnin Apprentice Elf

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    Thanks for the quick reply Ed.

    Now I'll have something to play with when I get home from the Tim McGraw concert tonight :D
     
  5. mschell

    mschell Full Time Elf

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    Ed and I had an email discussion around this, and I just wanted to post this here so it's available to everyone.

    I recently purchased 2 LOR DC boards. One of the interesting facts about mixing DIY and commercial controllers is the use of the "non-essential" pins on the RJ45. By non-essential, I mean anything besides the data signals (usually designated as D+/D-) Since RS485 is differential, you need those two signals, and only those two. Ground is nice, but not required, and could cause ground loops if you're not careful.

    So, in thinking of connecting those LOR controllers to the ECG and talking DMX to them, I wanted to be sure that the extra signals that LOR puts on the wire won't interfere.

    LOR uses the "inner" 4 wires/pins - 3,4,5,6. I believe the D+ is on 4 and D- on 5, so it's exactly opposite of Renard. LOR also puts at least +10V on pin3 and grounds pin 6. This could be a problem if the ECG or another controller chooses to ground pin 3. It turns out that another commercial controller - AL does just that, so you can't just plug a cable between them.

    From Ed's note above, the schematic, and the email conversation with Ed, it appears that both pins 3 and 6 on the ECG-DMXRen8 slaves are NC - no connection, with the exception of the terminal strip just below the RJ45 jack. That means that I could plug in a cable that passes pins 3 and 6 straight through and not have it effect or be effected by an LOR controller downstream.

    I'm hoping that the same (NC on pins 3 and 6) could apply to the DR4 and to the Pro version when it comes out, but just in case, it's been documented here...
     
  6. David_AVD

    David_AVD Good news, everyone!

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    I really wanted to bite my lip, but I can't let this pass without comment. RS485 is a 3 wire system, always has been and always will be. The "ground" you speak of is the common reference conductor. The reason that you can get away without explicitly connecting it in a lot of situations it that mains earth takes over that role.

    The reference is a part of the RS485 specification. It is also what protects the data pair against excessive common mode voltage. To avoid "ground loops" between grounded devices, using an isolated RS485 receiver is the right way to do it.

    If a standalone receiver (with or without receiver isolation) is powered by a plug pack (wall wart) and not otherwise grounded, connecting the common reference (ground) conductor is required. Sorry to harp on about this, but the myth that RS485 is a 2 wire system needs to die!
     
  7. mschell

    mschell Full Time Elf

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    I stand corrected on the "ground" reference for RS485.

    And in the DMX case shown by Ed, pins 7/8 are the reference signal path, connected to ground on the ECG by default.

    In the case of LOR controllers, it appears that these pins may or may not be connected to anything.
     
  8. David_AVD

    David_AVD Good news, everyone!

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    Hopefully I didn't come off as sounding too harsh. A lot of the time RS485 will work with only the data pair connected. Unfortunately, this only perpetuates the "RS485 is a 2 wire system" myth. I'm really keen for the info posted on ACL to be as accurate as possible. ;)
     
  9. AussiePhil

    AussiePhil Dedicated Elf Administrator

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    accurate is good,

    Before it gets queried, the TP3212 only uses 2 wires into the unit and is opto-isolated on the RS485 line.

    Cheers
    Phil
     
  10. David_AVD

    David_AVD Good news, everyone!

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    Phil & I had further discussion about this today. There should be no issue with the TP3212 boards when released.
     

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