Master Line Speed Command

Follower (Slave) Speed Percent 

  Enter a master speed command in percent, as whole numbers. Maximum speed is 100%. 

  Click "Master Line Speed" to enter the command.

  Enter a follower speed command in percent, as whole numbers.

  Click "Follower Speed Ratio" to enter the command.

  The follower in this example, can go from 1% of the master's speed, to two times (200%) the master's speed.

This system uses a typical "Master Reference Control". The actual control can be a multi-channel analog option card with signal isolation for each channel. It could be a PLC or signal isolator card as well. These options are generally used in multi-motor systems where one line speed command will be output to many drives. A master line speed command is given to one drive, and the others become "follower" drives. In this system, speed sensing feedback devices are used by each drive to compare the commanded speed with the actual speed. Closed loop control of the error between the actual and set speed provides good speed regulation.

Multiple drives can be given speed commands using one input to the master reference control.

Scaling of the speed command of each drive is on board the master reference control.

• When coordinated control is NOT desired, switching to independent control can be complex.

• Scaling of each drive speed can require running product for a considerable time.

• PLC based master reference controls can have many parameters such as bias, gain and offset.

• Troubleshooting each channel of speed reference can be difficult.

• Master reference control option device (analog card, PLC, etc)

• Power supply, fused

• Electrical enclosure to house option device and peripheral devices 

• 2 vsd's

• 2 motors

• 2 speed sensing feedback devices (encoder is shown) Can be motor shaft mounted or machine shaft.

Easy

Difficult