Parker Hannifin 
Immediate Mode 
While a program is running, the master velocity can be changed for 
a master (and all axes attached to it). The change is instantaneous, 
and takes effect even if the axis or axes are moving. 
Use the FOV (Set Feedrate Override) command to set a floating-
point scaling factor to adjust the master velocity. If a move is in 
progress, the master uses the established acceleration or 
deceleration ramp to adjust to the new velocity. 
NOTE: The FOV command does not change the master velocity 
permanently and the change is not saved. To make a 
permanent change, adjust the master velocity in the 
program code either manually or through the Configuration 
Wizard. 
For more information about feedrate override, see the FOV 
command in the ACR Command Language Reference. 
Example 
The following is typed in at the prompt by the user. It reduces the 
master velocity for all attached axes to 75%, then 50%, and then 
returns the velocity to 100%. 
FOV 0.75 
FOV 0.50 
FOV 1.00 
Differences Between FOV and VEL 
While a program is running, both the FOV and VEL (Set Target 
Velocity for a Move) commands can be set, but each affects 
motion differently: 
•  FOV immediately affects all axes attached to the master. 
•  VEL is buffered in memory. The newly commanded velocity 
does not take effect until current motion is completed. 
52    Programmer’s Guide