Elektriajamite 3. labor (0)

Tallinn University of Technology
Department of Electrical Engineering
Report on laboratory work 3 on General Course of Electrical Drive
SERVO DRIVE (FESTO)
Jüri Lina
666BMW
Group M16 Variant 2
Tallinn 2014
1. Functional Diagram
Component list:
PC with Wmmemoc software
SEC-AC-305 controller
MTR-AC-55 servo motor with encoder
External 24VDC power supply unit
Test stand with slide and limit switches
4. Tables of observations
Task
Operation / Record
Observation
1
Measure the slide position at Limit switch 1
Slide moved to the right, Limit 1 reached at 1,46
2
Turn potentiometer slowly counter -clockwise
Slide started slowly moving left, movement speed increased when potentiometer was further turned counter-clockwise.
Return potentiometer to 0
Slider movement speed slowed down until stopping when potentiometer was returned 0
3
Position number
Calculated destination
Observed destination
3
2.05
2.05117
4
4.1
4.11723
5
2.05
2.05439
4
Slowly turn the potentiometer fully counter-clockwise. What Torque the slide starts to move at.
The slider starts moving at -0,07 Nm Torque. Returning the slider to 0 stopped movement.
Slowly return to 0 by turning the potentiometer clockwise.
While holding the slide manually in the end position, slightly run the slide to the other end. What Torque the slide starts to move at?
The slide starts moving at -0,02 Nm Torque.
5. Table with my program
The parameters entered into the Position window under Pos 3, Pos 4 and Pos 5 were the following :
Position
Position [R]
Running speed [rpm]
Positioning run
Acceleration [msec]
Deceleration [msec]
3
2.05
400
absolute
100
100
4
4.1
500
absolute
100
100
5
2.05
200
absolute
400
400
Explanations:
Position- Entry number in program
Position [R] – position value that the motor should achieve
Running speed- maximum speed at which the motor will perform the command
Positioning run- determines positioning mode, which may be relative (calculated from the last position), or absolute (calculated from the reference point).
Acceleration – determines the time, the motor accelerates to full movement speed (the lenght of acceleration ramp )
Deceleration- determines the time, the motor decelerates to full movement speed (the lenght of deceleration ramp)
6. Solutions to the problems
3.1 What signals SEC-AC and testbox exchange?
SEC-AC and testbox exchange the following signals:
TD-RD (Transmitted Data – Received Data)
DTR-DSR (Data Terminal Ready - Data Set Ready)
RTS-CTS(Request to Send- Clear to Send)
3.2 Explain the needs in speed control and its problems
Speed control is needed to achieve the requirements of the task of the motor, provide safety for the operator , ensuring optimal power usage and service life of the mechanical parts involved.
Examples of problems in speed control:
Designing a motor capable of the needed speed characteristics .
The design of a reliable encoder, because some methods (like optical reading ) may not work well at high speeds.
Ensuring smooth acceleration and deceleration.
Optimal usage of motor braking energy.
3.3 How can you change the speed
By supplying the motor with more or less power.
In this laboratry work:
When manually controlling the motor with the testbox- by turning the potentiometer in the desired direction.
When controlling the motor with the program Wmemoc – by setting the speed slider to the desired value in the program settings.
3.4 What factors affect the resolution of a position the slide is moving to?
Running speed and acceleration/deceleration ramps affect the accuracy of the positioning. Sharper movement means less accuracy. Also differences when the positioning run is set in absolute or relative mode.
3.5 How long can a ramp be?
Ramp lenght is determined by the program setting, where the user determines how much time the acceleration/deceleration will take and the capabilities of the controller. In the case of this lab it is limited by the parameters of the motor and the lenght of the slide.