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

1 May 1998
luberth@
http://luberth.com/~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 +----------+