What is the Axis Velocity
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?