Stepper motor translator and drive circuits typically require STEP and DIRECTION input signals to operate. These signal can be provided by PLC's, stepper indexers or stand-alone digital circuitry. The ADR products can be used to provide these signals using digital I/O and commands to SET and RESET the I/O lines.  The host can then control and   keep track of stepper position.

Figure 1.  Basic Stepper Motor Application

The demand on the bandwidth of the  communication link between the host and standard ADR products limits step speeds to about 150 steps/second at 9600 baud. To overcome this limitation the ADR2100 has a complete dual stepper motor indexer built in to provide precise step and direction signals to stepper drive circuits with minimal use of the communication link between the host and ADR products. the indexer has the following features;

• Simultaneous control of two stepper motors
• Programmable speed setting ( 0 -1000 steps/second in 10 step/second increments)
• Indexed moves of up to 50,000 steps
• Monitoring of limit switches ( two per axis )
• Interrupt generation ( programmable )
• Emergency Stop function
• Easy to use command set
• Position registers readable on-the-fly
• Speed change on-the-fly

The stepper motor indexer uses port A of the ADR2100 when configured for STEPPER MODE. A Typical connection of a stepper motor linear slide application is shown in figure 2.

Figure 2 Typical Stepper Motor Application with ADR2100 as indexer.

The limit switch inputs have built in pull-ups allowing use of mechanical or inductive proximity switches. ( NPN) When limit switches are activated, movement in corresponding direction is disabled and an interrupt is generated ( if enabled ) The commands ( preliminary list ) to use the indexer are;

CPASTEP <cr>

Configures PORT A as stepper indexer.

MSddd <cr> ( ddd = 000 to 100 )( ddd*10 = actual speed setting)

Sets speed of move from 0 to 1000 steps/sec  in 10 step/sec increments. Speed is changable on the fly and has a worst case accuracy of 1%

LAFddddd<cr> ( ddddd= 00000 to 50000 )

Loads stepper motor A move register with steps to move Forward ( CW )

LARddddd<cr> ( ddddd= 00000 to 50000 )

Loads stepper motor A move register with steps to move Reverse ( CCW )

LBFddddd<cr> ( ddddd= 00000 to 50000 )

Loads stepper motor B move register with steps to move Forward ( CW )

LBRddddd<cr> ( ddddd= 00000 to 50000 )

Loads stepper motor B move register with steps to move Reverse ( CCW )

QA<cr>

Returns present number of steps to finish move of stepper motor A

QB<cr>

Returns present number of steps to finish move of stepper motor B

G<cr>

Begins move of both stepper motors.

E<cr>

Emergency Stop, stops all motor movement.

EI<cr>

Enables interrupt generation.

Additional features of the ADR2100 may enhance the application such as using the PWM outputs for motor torque control.

For additional Information please contact Tom Fortin at our Sudbury office. (705) 671-2652

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