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Chapter 3
Signal Connections
Power Connections
The NI 951x drive interface modules require an external power supply. An onboard regulator
generates a +5 V output supply from the V
sup
input for both internal and external usage. The
positive terminal for the power supply must be connected to V
sup
and the reference must be
connected to COM.
Note
You can connect the external power supply to the V
sup
input provided on
either DSUB or MDR connectors. Do not connect more than one external power
supplies to the module.
Command Signals
The following signals control the stepper or servo drive.
Stepper Command Signals
Step (CW)± and Direction (CCW)±
These signals are the NI 9512 drive interface module stepper command outputs.
The stepper output mode is software configurable for compatibility with various third-party
drives. The NI 9512 module supports both industry standards for stepper command
signals—step and direction, or clockwise (CW) and counterclockwise (CCW) pulse outputs, as
follows:
•
When step and direction mode is configured, each commanded step (or microstep)
produces a pulse on the step output. The direction output indicates the commanded
direction of motion, either forward or reverse. Refer to Figure 3-1 for an illustration.