Digital Speed Controls for Master and Follower Drive Variable Speed Drive Reference with tachometer or encoder feedback. Master Slave Motor Control. Master Follower Motor Control. Synchronize Motor Operation. Speed Feedback Motor Control.

Burhans Research Motor Control Systems
Master Line Speed Command	Follower (Slave) Speed Percent


Digital I/O #M1	Digital I/O #F1
Digital I/O #M2	Digital I/O #F2
Pulse Output

Status

Directions:

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 2 times (200%) of the master's speed.

System Basics

This system uses two digital speed controls that function like speed potentiometers. Speed command outputs to each drive or entered via a keypad, and the usual parameters of speed signal level, and scaling can be displayed. The system uses the auto-reference input on each drive. Each drive will be set up for external reference source. Speed sensing feedback from each motor (or driven machine shaft) provides very good speed regulation. The key feature in this system is the ability to parallel connect the master speed feedback to the follower control as an "auxiliary" feedback. The control monitors the error between the master feedback, and its own feedback.

Benefits of this system

Drives can be mixed ie DC, eddy current or AC.
Scaling the speed commands of each control is flexible.
Good speed reference regulation based on the resolution of the controller output signal.
Very good speed regulation due to speed feedback sensing.

Drawbacks and Pitfalls of this system

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.
The programming of the controllers on startup can be complicated.
Troubleshooting speed control of each drive can be difficult.
Speed feedback means that the drives controller's ability to regulate motor speed is precise.

Basic Bill of Materials for the system shown (excluding power transmission, etc.)

2 vsd's
2 motors
2 Digital Speed Controllers
2 speed sensing feedback devices (motor shaft mount or machine shaft mount)

	Easy				Difficult
	1	2	3	4	5
Set up Complexity					X
Troubleshoot Complexity					X
System Operation Flexibility				X