Intelligent Motion Systems Ultra Miniature High Performance Microstepping Drpive 用户手册

CURRENT 

REDUCTION 

RESISTOR 

 
Built into the IM481H is the ability to automatically reduce the current in the motor 
windings after the completion of a move.  The reduction occurs approximately .5 seconds  
after the last positive going edge of the Step Clock input.  The IM481H will then revert 
back to the original current setting at the next positive going edge of the Step Clock input. 
 
To utilize this feature, the current reference output must be used to adjust the output 
current of the IM481H and a resistor must be connected between pins 3 & 4 (see Figure 
6).  The value of the resistor will determine the amount of current reduction. 
 
The amount of current per phase in the current reduction mode is related to the value of 
the current reference resistor and the current reduction resistor.  When the current 
reduction circuit is activated, the current reduction resistor is paralleled with the current 
adjustment resistor. The parallel combination of the current reference and current 
reduction resistors determine the reduced current level.  The relationship between the 
output current and the resistor's values is as follows: 
 

                                                         .001 x *R(Current Adjust) x R(Current Reduction)  

      Output Current Reduced (Amps)= 

                                                       R(Current Adjust) + R(Current Reduction) 

 

 OR   

 
                                                              Output Current Reduced x R(Current Adjust)   
                R(Current Reduction) =   
                                                        .001 x R(Current Adjust) - Output Current Reduced  
 
NOTE: Resistor  values are in ohms. 
 
 

When connecting the current reduction resistor between pins 4 and  5, the 
connections should be made as short as possible to help minimize noise 
coupled into the driver. 

CURRENT 

ADJUSTMENT 

RESISTOR