SD-800(DOCS)          Optical Printer Control System    SD-800(DOCS)

NAME
    sd-800 - OPCS 8 channel "stepper distribution" (SD) card

DESCRIPTION
    The OPCS "Stepper Distribution" card (SD-800) was designed to
    simplify wiring between the computer step pulse generator card
    (e.g. RTMC16, RTMC48, Kuper Industrial, A800..) and the stepper
    motor driver modules (Centent, Gecko, LeadShine, etc) by breaking
    out the DB-37 connector into separate RJ-45 patch cables, one per
    stepper drive channel.

    This board really has no active features on it, other than a fanout
    to simplify wiring. Optional pullup resistor networks can be used
    if the application requires open collector outputs from the card
    to be pulled up to +5V for the idle state to prevent noise.

    As of this writing, there is only one version of the board, REV 0,
    which looks like this:


                               DB-37 PORT
                        (To RTMC or A800 cards)
                          ____________________
               __________|____________________|_________
              |          |                    |         |
              |          |____________________|         |
              |                                         |
              |                                         |
              |                                         |
              |                                         |
              |     ______________________________      |
              |    |                              |     |
              |    |    A      B       C      D   |     |
              |    |______________________________|     |
              |    |                              |     |
              |    |    E      F       G      H   |     |
              |____|______________________________|_____|

                    \____________________________/
                             Eight  RJ-45
                              Connectors
                              (Two Tiers)

    Typically the female DB-37 connector on the board is connected
    to the DB-37 connector on the ISA stepper pulse generator card
    plugged into the the DOS computer using 6' male/male cable.

    And separate RJ-45 patch cables are wired to the A/B/C/D..
    ports at the bottom of the board, which run out to the individual
    stepper drives (Centent, Gecko, LeadShine, etc).

    The DB-37 follows Kuper's pinout; see 'man kuper' for more info.
    The RJ-45 pinout diagram is on the board, but is basically:

        RJ-45             WIRE      CENTENT       GECKO        LEADSHINE
        PIN#  SIGNAL      COLOR (*) DRIVE         DRIVE        DRIVE
        ----  ----------  --------  -----------   -----------  ------------
         1    GND         -         N/C           N/C          N/C
         2    GND         -         N/C           N/C          N/C
      _  3    GND         -         N/C           N/C          N/C
 DIR |   4    DIRECTION   BLU       DIRECTION     (8) DIR      DIR-(DIR)
     |_  5    +5V         WHT/BLU   +5 VOLTS DC   (10) COMMON  DIR+(5V-24V)
      _  6    GND         -         N/C           N/C          N/C
 STP |   7    +5V         WHT/BRN   N/C           N/C          PUL+(5V-24V)
     |_  8    STEPS       BRN       STEP PULSE    (9) STEP     PUL-(PUL)


       (*) Premade RJ-45 patch cables for cat5 and cat5e usually have
           the standard wire colors shown above. For the signals used,
           the wiring colors are the same for 568A and 568B.

     Basically only 4 of the 8 wires are used. In some cases only 3 wires
     are used (Centent & Gecko).

     Please note these signals are DIRECTLY FROM THE COMPUTER MOTHERBOARD,
     so be very careful with them. Do not let them short to chassis ground
     on the printer, or to each other.

RJ-45 CABLE TERMINATION
-----------------------
    For unused (N/C) wires, be sure to isolate them from each other
    to prevent shorts. Cut them short to the stripped insulation or
    stagger the lengths of the unused wires to prevent the frayed
    ends from shorting into each other.

    Wrap the unused conductors with a small piece of heat shrink:


                       4 wires to
                    Drive Terminals
                      ___________
                     /           \
                       
                      ▐▌ ▐▌ ▐▌ ▐▌  <-- tinned wire tips
                      ▐▌ ▐▌ ▐▌ ▐▌ 
                      ▒▒ ▒▒ ▒▒ ▒▒
                      ▒▒ ▒▒ ▒▒ ▒▒  4 unused wires
                      ▒▒ ▒▒ ▒▒ ▒▒    _________
                      ▒▒ ▒▒ ▒▒ ▒▒   /         \
                   ...▒▒.▒▒.▒▒.▒▒.................
                   :  ▒▒ ▒▒ ▒▒ ▒▒                :
                   :  ▒▒ ▒▒ ▒▒ ▒▒   ▒▒           :
                   :  ▒▒ ▒▒ ▒▒ ▒▒   ▒▒ ▒▒        :
                   :  ▒▒ ▒▒ ▒▒ ▒▒   ▒▒ ▒▒ ▒▒     :   <-- heat shrink wrap
                   :  ▒▒ ▒▒ ▒▒ ▒▒   ▒▒ ▒▒ ▒▒ ▒▒  :
                   :▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓:
                   :▓                           ▓:
                   :▓                           ▓:
                   :▓...........................▓:
                    ▓                           ▓
                    ▓           RJ-45           ▓ 
                    ▓           CABLE           ▓ <-- RJ-45 outer insulation
                    ▓                           ▓



    If heat shrink is not available, a blob of black liquid electrical
    tape at the end of the cables outer insulation can be used instead:


                       4 wires to
                    Drive Terminals
                      ___________
                     /           \
                       
                      ▐▌ ▐▌ ▐▌ ▐▌  <-- tinned wire tips
                      ▐▌ ▐▌ ▐▌ ▐▌ 
                      ▒▒ ▒▒ ▒▒ ▒▒
                      ▒▒ ▒▒ ▒▒ ▒▒  4 unused wires
                      ▒▒ ▒▒ ▒▒ ▒▒    _________
                      ▒▒ ▒▒ ▒▒ ▒▒   /         \
                  ::::▒▒:▒▒:▒▒:▒▒::::::::::::::::::
                 :::::▒▒:▒▒:▒▒:▒▒:::▒▒::::::::::::::
                 :::::▒▒:▒▒:▒▒:▒▒:::▒▒:▒▒:::::::::::
                 :::::▒▒:▒▒:▒▒:▒▒:::▒▒:▒▒:▒▒::::::::
                ::::::▒▒:▒▒:▒▒:▒▒:::▒▒:▒▒:▒▒:▒▒::::::
               :::::▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓:::::  <-- blob of "Liquid
               :::::▓:::::::::::::::::::::::::::▓:::::      Electrical Tape"
               :::::▓:::::::::::::::::::::::::::▓:::::
                ::::▓:::::::::::::::::::::::::::▓::::
                    ▓                           ▓
                    ▓           RJ-45           ▓ 
                    ▓           CABLE           ▓ <-- RJ-45 outer insulation
                    ▓                           ▓


    Be sure the ends of the unused wires are well isolated from
    the open air, and from each other during drying.

ISOLATE UNUSED RJ-45 CONDUCTORS
-------------------------------
    Unused conductors on the SD-800 and SD-1600 are usually just the
    chassis grounds, and are not critical to isolate from each other.

    However, unused conductors on the PIO-800 Parallel Input/Output
    boards are typically +5V and GND from the computer, and therefore
    should be /carefully isolated/ from each other.

    When wiring SD-800 and SD-1600 boards to the Centent or Gecko drives,
    strip the two +5V signal wires and twist them together before tinning
    with solder. Don't let one of the +5V signal wires hang loose,
    because if it touches anything else, it will short the computer's
    +5V supply, which at best reboots the machine, or at worst toasts
    the computer's mother board.

STRIPPING RJ-45 CABLES
----------------------
    When wiring to the screw clamp terminals, tin the wires (if they're
    stranded) before inserting them, to prevent wire fraying and shorts
    from stray pieces of stranded wire. 

    When tinning stranded wire, first twist the strands into a spiral,
    then dip the twisted strands into some flux. This way when solder is
    applied, the extra flux helps the solder wick down the conductors
    beneath the insulation, stiffening the conductors beyond insulation's
    edge, preventing flexion at the end of the wire.

    Tinning will also cover over any nicks in the conductors that may
    have occurred during wire stripping with solder, stiffening the nicks,
    preventing fatigue:


                  BEFORE Solder Tinning
                  ---------------------

                              
                          ████
                          ████
                          ████
                          ████       
                          ████
                          ██¡    <-- copper conductor "nicked"
                          ████       during insulation stripping
                       ▒▒▒▒▒▒▒▒▒▒
                       ▒▒▒▒▒▒▒▒▒▒
                       ▒▒▒▒▒▒▒▒▒▒  <-- single conductor
                       ▒▒▒▒▒▒▒▒▒▒        insulation
                       ▒▒▒▒▒▒▒▒▒▒


                   AFTER Solder Tinning
                   --------------------

                          ████
                          ████
                          ████
                          ████
                          ████       
                          ████   <-- "nick" covered by solder
                          ████
                       ▒▒▒▒▒▒▒▒▒▒
                       ▒▒▒▒▒▒▒▒▒▒ <-- solder wicked down wire
                       ▒▒▒▒▒▒▒▒▒▒     below insulation edge
                       ▒▒▒▒▒▒▒▒▒▒
                       ▒▒▒▒▒▒▒▒▒▒

RJ-45 STRAIN RELIEF
-------------------
    Don't let the cables hang by their screw terminals at motor drives
    and/or termination at home sensors. Casual wire flexion will cause
    wire fatigue, leading to breakage or intermittent signal dropouts.

    Secure cables to the chassis or drive units by their insulation
    within approx 6" of the wire termination point using zip ties or
    nylon straps/cleats.


AUTHOR
    Greg Ercolano / Seriss Corporation 2021
© Copyright 1997 Greg Ercolano. All rights reserved.