PLC Motion Control & Drive Systems 2

Question 1

What is the primary function of an encoder in a servo motor system?

Accepted Answer

To provide real-time position and velocity feedback to the servo controller

Answer

To regulate voltage supplied to the motor windings

Answer

To limit peak motor current during startup

Answer

To convert AC supply power to DC bus voltage

Question 2

What fundamentally distinguishes a servo drive from a standard VFD?

Accepted Answer

Servo drives use encoder feedback for precise closed-loop position and torque control

Answer

Servo drives only operate with AC induction motors

Answer

Servo drives operate exclusively at voltages below 24V DC

Answer

Servo drives cannot communicate digitally with PLCs

Question 3

In PLC motion control, what does performing a 'homing' routine accomplish?

Accepted Answer

It establishes a known reference position so the controller knows the axis's absolute location

Answer

It returns the PLC program to its default factory settings

Answer

It sets the maximum travel speed limit for the axis

Answer

It transfers the motion program from PLC memory to the drive

Question 4

A quadrature incremental encoder outputs two channels (A and B) that are 90° out of phase. What information does the phase relationship between A and B provide?

Accepted Answer

Direction of rotation (clockwise vs. counterclockwise)

Answer

Absolute shaft position from a fixed reference

Answer

Motor winding temperature

Answer

Supply voltage level

Question 5

What is the purpose of a 'jog' command in a PLC motion control application?

Accepted Answer

Move the axis continuously at a slow speed only while the command signal is held active

Answer

Command the axis to move to a programmed absolute position at full velocity

Answer

Execute the automatic homing sequence at startup

Answer

Stop the servo drive immediately with zero deceleration

Question 6

What is the function of a 'torque limit' parameter in a servo drive configuration?

Accepted Answer

It caps the maximum force the servo can apply, protecting mechanical components from overload

Answer

It increases the motor's maximum operating temperature threshold

Answer

It sets the maximum allowable shaft speed in RPM

Answer

It defines the number of encoder pulses per revolution

Question 7

According to PLCopen motion control standards, which function block commands an axis to move to a specified absolute position?

Accepted Answer

MC_MoveAbsolute

Answer

MC_MoveVelocity

Answer

MC_Stop

Answer

MC_Home