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4-4 Input/ Output MN1940

4.3 Logic inputs
TheDSM has threeoptically isolated logic inputs. These inputs are isolated to minimize or
eliminateelectr ical noise coupled onto the drive control signals, and are over -voltage
protected. The inputs may be configured as either sinking inputs or s ourcing inputs (model
dependent,see s ection 4.3.3), with the Optocoupler Reference (white) lead as thereference.
Thisallow s the DSM to be interfaced to a variety of controllers.
DSM
Optocoupler
reference
Stepclock
input
Direction
input
Enableinput
HCPL0630
PS2701-1
750R
HCPL0630
470R
470R
Figure8 - Opto-isolated digital input circuit (sinking only)

4.3.1 Logicinput descriptions

4.3.1.1 Stepclock(orange f lying lead)
Thestep c lock input is where the motion clock from the contr ol circuitry will be connected. The
motorwill adv ance one microstep in the plus or minus direction (based upon the s tate of the
directioni nput) on the step clock edge that causes the opto-isolator tobeactiv e. The size of
thisinc rement or decrement will depend on the microstep resolution setting. The max imum
frequency on the step clock input is 2.0 MHz, with a minimum pulse w idth of 400 ns.
4.3.1.2 D irection (blue flying lead)
Thedirec tion input controls the CW/CCW direction of the motor. A logic high (default,
unconnected) will cause the motor to rotate in the CW direction (seen while look ing at the face
ofthe motor). A logiclowon the input w ill cause the motor to rotate in the CCW direction. This
inputis s ynchronized to the positive going edge of the step clock input.Thedirec tion input
maybe c onnected by means of a switch.
4.3.1.3 E nable (brown flying lead)
Thisinput c an be used to enable or disable the driver output circuitry. A logic high (when t he
enableswi tch is open, see Figures 9 and 10), causes the driver outputstobe enabled and
stepc lock pulses will cause the motor to advance. A logiclow(w hen the input switch is