ICPDAS STEP-200
2-Axis Stepping Motor Control Card
 

Odering Information

STEPPER-200 : 2-Axis Stepper Motor Control Board
 

Option :

DN-25: 25-pin Screw Terminal Board
 


Enviromental

  • Operating temp range : 0C 50C
  • Storage temp range : -20C to 70C
  • Power Requirements: +5V@ ???mA typical , ???mA max
  • Dimension : 108 mm x 167 mm
Features & Specifications
  • 2-axis independent, simultaneous stepper motor control / servo motor control ( pulse input type )
  • Step rate : 1pps~250Kpps
  • Max. step count : +/-   steps
  • DOS, windows 95, windows NT driver
  • Embedded Micro-processor
  • Command type interface
  • linear, circular interpolation
  • Acceleration / Deceleration : Automatic trapezoidal acceleration / deceleration
  • Output pulse modes : CW/CCW or pulse / direction
  • Output polarity can be programmable
  • 2500Vrms optical isolated signal output
  • 5 optical isolated digital inputs per axis for limit switches
  • Pullups: All input have internal 10K pullups to + 5V
  • Power Requirements: +5V    mA typical ,   mA max
Block Diagram
STEP-200 is a two axes commanded-based Stepping motor control card. It can be used in pulse-type servo motor control card. It equipped a 2Kbytes-FIFO. FIFO is used to receive motion command from host PC. The ŁgP is used to generate  profile and control the mechanism of protection. The two DDA chips is used to execute DDA function when interpolation command is executed.. The 2500Vrms optical isolation is designed for industrial application. 
The DDA chip is the heart of STEP-200 , it generate equal-space pulse train corresponding to specified pulse number during a DDA period. This mechanism is very useful to execute pulse generation and interpolation function. The DDA period can be determined by DDA cycle. Table(1) shows the relation among DDA cycle, DDA period and output pulse rate. When DDA cycle is set to 1, the DDA period is equal to 8.192ms. The output pulse number can be set to 0~2047, therefore the maximum output pulse rate will be 249.877kpps. The minimum output pulse rate is 0.96pps when set DDA cycle=254 (DDA period = 1040.384ms).
Table(1) The Relation between DDA cycle, DDA period and output pulse rate.
DDA cycle DDA period Max. pulse
rate(n=2047)		 Min. pulse 
rate(n=1)
1 8.192ms 249,877pps 122pps
2 12.288ms 166,585pps 81pps
3 16.384ms . .
. . . .
N (N+1)*4.096ms 2,047/(DDA period) 1/(DDA period)
. . . .
254 1040.384 1,967pps 0.96pps
The DDA cycle can be set by MSTEP2_SET_VAR(DDA_cycle, Acc_Dec, Low_Speed, High_Speed) command which decribed in charpter 3. The selection criterion of DDA cycle is described as the following.
 

(1) The required max. output pulse rate.
PRmax =VMax/(60*N)
PRmax =2047/((DDA cycle+1)*4.096ms)

PRmax : max. output pulse rate.
Vmax   : max. speed (rpm).
N         : the pulse number of stepping motor per revolution.
              (pulse/rev).

2. The required speed resolution.
The maximum output pulse number is Np(0~2047), therefore the speed resolution is Vmax(max. speed)/Np. The DDA cycle can obtain as following.
PRmax =Np/((DDA cycle+1)*4.096ms)

3. Large DDA cycle (DDA period), it will generate vibration between different pulse input which generally can be observed during acceleration or deceleration. So, the small DDA cycle , the smooth acceleration/deceleration curve as long as the speed resolution can be acceptable.