Baldor MN1940 Logic inputs, Logic input descriptions, Step clock orange flying lead

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4.3 Logic inputs

The DSM has three optically isolated logic inputs. These inputs are isolated to minimize or eliminate electrical noise coupled onto the drive control signals, and are over-voltage protected. The inputs may be configured as either sinking inputs or sourcing inputs (model dependent, see section 4.3.3), with the Optocoupler Reference (white) lead as the reference. This allows the DSM to be interfaced to a variety of controllers.

	DSM
Optocoupler	470R	HCPL0630
reference
Step clock
input
	470R	HCPL0630
Direction
input
	750R	PS2701-1
Enable input

Figure 8 - Opto-isolated digital input circuit (sinking only)

4.3.1 Logic input descriptions

4.3.1.1Step clock (orange flying lead)

The step clock input is where the motion clock from the control circuitry will be connected. The motor will advance one microstep in the plus or minus direction (based upon the state of the direction input) on the step clock edge that causes the opto-isolator to be active. The size of this increment or decrement will depend on the microstep resolution setting. The maximum frequency on the step clock input is 2.0 MHz, with a minimum pulse width of 400 ns.

4.3.1.2Direction (blue flying lead)

The direction 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 looking at the face of the motor). A logic low on the input will cause the motor to rotate in the CCW direction. This input is synchronized to the positive going edge of the step clock input. The direction input may be connected by means of a switch.

4.3.1.3Enable (brown flying lead)

This input can be used to enable or disable the driver output circuitry. A logic high (when the enable switch is open, see Figures 9 and 10), causes the driver outputs to be enabled and step clock pulses will cause the motor to advance. A logic low (when the input switch is

4-4 Input / Output MN1940