What is the Axis Velocity

Owned by Perla Madrigal (Unlicensed)
Last updated: Jul 30, 2024 by James Wiley
2 min read

 Products: ACR7000, IPA. ACR9000, 9030,9040,9600,9630,9640, Aries Controller (AR-xxCE)

The ACR controllers provide a number of different parameters to view and monitor axis velocity.

Velocity (Monitor): The TOTAL (CAM + Gear + Jog + Coordinated) commanded velocity for the axis. Units are counts/second.

Current JOG VEL:  The current commanded velocity of a JOG move

Encoder Velocity: Signed change in encoder counts since the previous servo period. EPL axes do not populate the encoder velocity parameter. The EPLD Velocity parameter serves this function for EPL axes.
EPLD Velocity: Signed change in EPL drive's encoder counts since the previous servo period.

RPM: Revolutions per minutes are calculated and stored in this parameter, based on the value set in RPM factor. This value is only populated when RPM factor is greater than zero.

Smooth Encoder Velocity: Encoder counts/servo period. This is actually a filtered value, sampled and averaged over 50 servo periods. This value is used to calculate RPM and is only populated when RPM factor is greater than zero.

Notes:
RPM and Smooth Encoder Velocity are only updated when an axis is associated with an encoder or EPL drive, i.e, encoders without an axis and stepper axes will cannot use RPM and smooth velocity.
ACR Operating System 1.22 or greater is required to use RPM and Smooth Encoder Velocity for EPL drives.

 

Axis Number

 

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Monitor Parameters-Velocity

12315

12571

12827

13083

13339

13595

13851

14107

14363

14619

14875

15131

15387

15643

15899

16155

Current JOG VEL

12346

12602

12858

13114

13370

13626

13882

14138

14394

14650

14906

15162

15418

15674

15930

16186

Reserved Parameters

 

RPM Factor

12370

12626

12882

13138

13394

13650

13906

14162

14418

14674

14930

15186

15442

15698

15954

16210

RPM

12371

12627

12883

13139

13395

13651

13907

14163

14419

14675

14931

15187

15443

15699

15955

16211

Smooth Encoder Velocity

12372

12628

12884

13140

13396

13652

13908

14164

14420

14676

14932

15188

15444

15700

15956

16212

 

Using RPM factor

The controller will only populate RPM and Smooth Encoder velocity if RPM factor is greater than 0. The user needs to set the RPM factor.

RPM factor uses the following formula:

RPM Factor = 60/(Encoder Pulses per Unit * PERIOD)

Example

Axis0
Motor with 8000 pulses per revolution encoder
0.5 millisecond servo period
P12370=60/(8000*0.0005)
P12371: will update axis velocity in Revolution/minute

Alternatively, to display in revs/sec, set P12370=0.25
Default PERIOD for ACR7000 & ACR90x0 controllers is 0.0005 seconds.
Default PERIOD for IPA and Aries Controllers is 0.00025 seconds
To check the current PERIOD setting for the controller, type PERIOD at any terminal prompt.

SYS>PERIOD

0.0005

 

SYS>

 

 

Related FAQ:  How Fast is Servo Axis Moving?