Low Cost Stepper Motion
                    
					Stepper card - Includes:  External 4 axis step and direction board, RS232 and power cables, 7 outputs, 8 inputs which include 4 home inputs, 1 over travel input and 1 E-stop.  Can control standard stepper drives all for $395.  Can also control brush and brushless servo motors using servo drives that accept a step and direction signal. 
                    
                    STEPPER board does not include these features when compared to PCI or Ethernet boards
                    
                      - Not as many pulses per second
 
                        - Limited number of I/O points.  May need to add extra digital I/O card
 
                        - USB/RS232 communication which is slower that PCI/Ethernet
 
                        - Limited buffer size.  If computer is busy or hangs motion may pause.
 
                        - TTL level 5VDC I/O.  Would need to add relays to get higher voltages
 
                        - Feedrate over ride not as smooth or responsive
 
                        - Can not be expanded past 4 axes
 
                        - Mounts externally, not inside computer
 
                     
                     
                    
                   
                    
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