Connections for driving 3 unipolar stepper motors with parallel port 
With 3 input connections for home switches

1 May 1998 
Luberth@wxs.nl
http://home.wxs.nl/~luberth/plotter/plotter.htm

Luberth Dijkman 
Bangert 23
1619 GJ Andijk 
Nederland

ULN2803
8-bit 50V 500mA TTL-input NPN darlington driver.

Parallel Port 36 Centronics
                     +----------+             
Pin 2 ----------> D0-|1  +--+ 18|---> Stepper X  --> Winding-1-|------|   
Pin 3 ----------> D1-|2       17|---> Stepper X  --> Winding-2-|      |__ 
Pin 4 ----------> D2-|3       16|---> Stepper X  --> Winding-3-|      |  |
Pin 5 ----------> D3-|4  ULN  15|---> Stepper X  --> Winding-4-|------|  |
Pin 6 ----------> D4-|5  2803 14|---> Stepper Y  --> Winding-1-|------|  |
Pin 7 ----------> D5-|6       13|---> Stepper Y  --> Winding-2-|      |__|
Pin 8 ----------> D6-|7       12|---> Stepper Y  --> Winding-3-|      |  |
Pin 9 ----------> D7-|8       11|---> Stepper Y  --> Winding-4-|------|  |
(Parallel & Power)GND|9       10|-----Stepper-Power-5-To-30-V-DC---------|---x
* See note           +----------+                                Stepper power

Parallel Port 36 Centronics                       
                     +----------+ 
Pin 1  Strobe -------|1  +--+ 18|---> Stepper Z  --> Winding-1-|------|
Pin 14 Auto Feed-----|2       17|---> Stepper Z  --> Winding-2-|      |__ 
Pin 31 Init ---------|3       16|---> Stepper Z  --> Winding-3-|      |  |
Pin 36 SLCT IN ------|4  ULN  15|---> Stepper Z  --> Winding-4-|------|  |
                    -|5  2803 14|-                                       |
                    -|6       13|-                                       |
                    -|7       12|-                                       |
                    -|8       11|-                                       |
(Parallel & Power)GND|9       10|-----Stepper-Power-5-To-30-V-DC---------|---X
* See note           +----------+                                Stepper power

Parallel Port 36 Centronics Home Switches 

Pin 32 Error  <------------|----------------------/Switch home X ----|Ground
                           |
Pin 13 Select <----------- | ---|-----------------/Switch home Y ----|Ground
                           |    |
Pin 12 P.Emp  <----------- | -- | ---|------------/Switch home Z ----|Ground
                           |    |    |
                          |-|  |-|  |-|
                3 X R 10k | |  | |  | |
                          |-|  |-|  |-|
                           |    |    |
                           |----|----|----------------------------- + 5 V DC


* Parallel Ground Pin numbers 16,19,20,21,22,23,24,25,26,27,28,29,30,33




On the plotter i made 
i did not use a Z motor
i used a relay and a solenoid for pen up / pen down
                                          
                                               /    Solenoid(Hub magnet) 
                               Relay switch  /            -----
                                           /:            |\    |
Solenoid Power(Hub magnet) x-------------/  :   ---------|  \  |----x Ground
                                            :            |    \|
                                            :             -----
                                          -----      
                     +----------+        |\    |
Pin 1  Strobe -------|1  +--+ 18|--------|  \  |---|
Pin 14 Auto Feed-----|2       17|-       |    \|   | 
Pin 31 Init ---------|3       16|-        -----    |
Pin 36 SLCT IN ------|4  ULN  15|-        Relay    |
                    -|5  2803 14|-                 |
                    -|6       13|-                 |
                    -|7       12|-                 |
                    -|8       11|-                 |
(Parallel & Power)GND|9       10|------------------|--x Relay power 5 to ? V DC
* See note           +----------+