stepper motor control ab

Stepper Motor Controller1746 – HSTP11746 – HSTP1

J.ArumugamC & I Lab

Stepper Motor

• An electromagnetic actuator. It is anincremental drive (digital) actuator and isdriven in fixed angular steps.

– This mean that a digital signal is used todrive the motor and every time it receives adigital pulse it rotates a specific number ofdegrees in rotation.

J.arumugam PC - 100 2

Stepper basic

Phase 4

Rotor

Stator


Phase 1 Phase 3

Phase 2

Single-Coil Excitation - Each successive coil is ene rgized in turn

offoffoffona.1

Coil 1Coil 2Coil 3Coil 4Step


onoffoffoffa.4

offonoffoffa.3

offoffonoffa.2

Two-Coil Excitation - Each successive pair of adjace nt coils is energized in turn

offoffononb.1

Coil 1Coil 2Coil 3Coil 4Step


onoffoffonb.4

ononoffoffb.3

offononoffb.2

Interleaving the two sequences will cause the motor to half-step

Step Coil 4 Coil 3 Coil 2 Coil 1

a.1 on off off off

b.1 on on off off

a.2 off on off off


b.2 off on on off

a.3 off off on off

b.3 off off on on

a.4 off off off on

b.4 on off off on

Stepper vs. DC Motor


Stepper motor vs. servo motor


Types of Stepper motor

• Permanent Magnet (PM)– Rotor is magnetized with alternating North

and South poles situated in a straight lineparallel to the rotor shaft.

• Variable Reluctance (VR)


• Variable Reluctance (VR)– Consists of a soft IRON multi-toothed ROTOR

and a wound SATATOR.

• Hybrid– Combines the best features of the PM and VR

Permanent Magnet (PM)


Variable Reluctance (VR)


Hybrid


Advantages of Stepper Motors

�Position error is noncumulative. A highaccuracy of motion is possible, even underopen-loop control.

�Large savings in sensor (measurementsystem) and controller costs are possiblesystem) and controller costs are possiblewhen the open-loop mode is used.

�Because of the incremental nature ofcommand and motion, stepper motors areeasily adaptable to digital controlapplications.


Advantages of Stepper Motors

�No serious stability problems exist, evenunder open-loop control.

�Torque capacity and power requirementscan be optimized and the response can becontrolled by electronic switching.controlled by electronic switching.

�Brushless construction has obviousadvantages.


Disadvantages of Stepper Motors

�They have low torque capacity (typically lessthan 2,000 oz-in) compared to DC motors.

�They have limited speed (limited by torquecapacity and by pulse-missing problems dueto faulty switching systems and drive circuits).to faulty switching systems and drive circuits).

�They have high vibration levels due tostepwise motion.

�Large errors and oscillations can result whena pulse is missed under open-loop control.


Hybrid Step Modes

The hybrid stepper motor combines features ofboth the variable reluctance stepper and thepermanent magnet stepper to produce asmaller step angle.

• Full Step

• Half Step

• Micro Step


Full Step

• Standard hybrid stepping motors have 200 rotorteeth, or 200 full steps per revolution of themotor shaft.

• Dividing the 200 steps into the 360º of rotationequals a 1.8º full step angle.equals a 1.8º full step angle.

• Normally, full step mode is achieved byenergizing both windings while reversing thecurrent alternately. Essentially one digital pulsefrom the driver is equivalent to one step.


Half Step

• Half step simply means that the step motor isrotating at 400 steps per revolution.

• In this mode, one winding is energized and thentwo windings are energized alternately, causingthe rotor to rotate at half the distance, or 0.9º.the rotor to rotate at half the distance, or 0.9º.

• Although it provides approximately 30% lesstorque, half-step mode produces a smoothermotion than full-step mode.


Micro Step• Micro stepping is a relatively new stepper motor

technology that controls the current in the motorwinding to a degree that further subdivides thenumber of positions between poles.

• Micro stepping drives are capable of dividing afull step (1.8º) into 256 micro steps, resulting infull step (1.8º) into 256 micro steps, resulting in51,200 steps per revolution (.007º/step).

• Micro stepping is typically used in applicationsthat require accurate positioning and smoothermotion over a wide range of speeds.


Stepper Motor Controller Module + Stepper Motor Controller


Stepper Connection Diagram


Translator / Driver

• The stepper motor driver receives low-level signals from the indexer or controlsystem and converts them into electrical(step) pulses to run the motor.(step) pulses to run the motor.

• To drive a controllable amount of currentthrough the windings, and enabling asshort current rise and fall times as possiblefor good high speed performance


Translator / Driver

CW or Pulse

CCW or Direction


Bi-Clock signal

Pulse / Direction signal

AB – PLC Stepper module

PLC scan IOModule

IOModule

Stepper loopUpdate time


PLC Processor

Cycle Module Module

Stepper Module IO

Update time

AB – PLC Stepper module

PLC scanCycle

Stepper loopUpdate time

250ms


PLC Processor Stepper Module s IO

Absolute Position Maximum: +/- 8388607 PulsesVelocity : 1 to 250000 Pulses /Second

Acceleration / Deceleration rates 1 to 2000 pulses /ms/s

1746 – HSTP1 Stepper module overview


Our lab connection diagram

654321

1234

CN1CN2

AB-PLC

Red

Red white

GreenGreen white

CW +

CW -

CCW +CCW -

Stepping

NC


24 VoltDC

1AB-PLCSteppermodule

Steppermotor

SteppingDriver

+ -

PS466-01A (Stepper)6V / 1.2A

2-Ph, 1.8 deg / Step

IMS 200 - 220

IMS200 Driver

System GND


System GND

7.Sl No. Label

1. Power Supply input & Motor Lead Connector (CN1)

Connect motor leads to these terminals as follows :


JP1,JP2 & CN2,


JP3, JP4 & JP5


Stepper module Operating modes

• Configuration mode– The module does not operate until it has been

configured at least once.

• Command mode


– SLC processor can issue commands and activatedifferent operation or moves.

• Diagnostic mode– This mode allows you to test your program and wiring

by connecting the loop back wires at the translator.

Before - Configuration mode

�Determine which inputs are used.�Determine the active level of inputs used.�Set whether just the encoder marker or a

proximity limit switch and encoder markercombination is used for homing.

�Determine if a quadrature encoder will be used.�Select whether the Module output is a pulse train

with direction command or a CW pulse train andCCW pulse train.

�Select between configuration mode andcommand mode.


Words - for Configuration mode


Configuration - Word 0

Any one or both bitMust be set


Bit 4 or 4 & 5Must be set

Bit 8 & 9 Both settingAre Not valid

Configuration - Word 0 cont…


Configuration - Word 1


Configuration - Word 2 and 3


Command mode• Absolute Moves• Relative Moves• Hold Moves• Resume Moves


• Immediate Stop Operation• Homing Operation• Jogging Moves• Preset Operation• Reset Error

Programming Command Mode - (Word 0)


Output command Bits for Word 0


Output command Bits for Word 0 cont…


Programming Command Mode - (Word 1 to 7)


Example files


stepper motor control ab

Documents