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Real Applications

7.4A Conveyor Application using several MICROMASTERs

MICROMASTERs are used to control short conveyors. Each conveyor is used as a holding point while products are sorted. The products are moved forward by rapid acceleration of the conveyors under computer control.

7.4.1Advantages

·Controlled acceleration rates ensure product is moved as fast as possible without damage.

·No direct on line switching of motor; no shock loading or current inrush.

·Drive status and parameters can be continuously monitored via serial link.

·Settings can be changed via serial link.

·Small size allows drive and control system to be mounted under conveyor and close to motor.

7.4.2System Specifications

Motor

750W 400V 3 phase induction motor.

Control System

Custom computer system communicating with central controller.

Drive

MICROMASTER MM420 750W 400V

Drive Control

Digital input control with 1 or 2 fixed frequencies, alternative

Interface

ramp rate selection, output relays.

7.4.3Application Details

Up to five inverters and motors are used in conjunction with five conveyors and a local computer controller. Three are shown below. The computer is used to set the parameters and to monitor drive operation. Actual control and fault monitoring is via the digital inputs and relay outputs. This example uses a BiCo (Binary Connector) function which connects digital input 3 to the ‘Select Jog Ramp times’ functions. For the second conveyor controller shown below the faster ramp times and second fixed frequency can be selected using digital inputs 3 and 2, connected to the control relays as shown in Figure 7-4.

Fault Loop

RS485

Monitor

14 15

PE

10 11

14 15

PE

10 11

14 15

PE

10 11

RS485

 

RS485

 

RS485

 

 

 

RL1

 

 

RL1

 

 

RL1

I/Ps:

7 6 5

2 (0V)

I/Ps:

7 6 5

2 (0V)

I/Ps: 7

6 5

2 (0V)

 

 

System 0V

 

 

System 0V

 

 

System 0V

 

 

Run Relay #1

 

 

Run Relay #2

 

 

Run Relay #3

 

 

 

 

 

High Speed Relay

 

 

 

 

 

 

 

High Acceleration Relay

 

 

Inverter/motor #1 - Transfer Belt

Inverter/motor #2 - Load Belt

Inverter/motor #3 - Feed Belt

Figure 7-4 Conveyor Application

MICROMASTER Applications Handbook

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