Delta Tau GEO BRICK LV User Manual

 

 

The units of the TM time are milliseconds; the units of the F velocity are the user length (or angle) units of 
the feedrate axes divided by the time units as defined by coordinate system variable Isx90 in milliseconds.  
If Isx90 is at the default value of 1000, the F units are length units per second; if Isx90 is set to 60,000, 
the F units are length units per minute. 
If no F or TM value is specified after power-up/reset, the value of Isx89 is used for the moves as a feedrate 
value.  Any F value specified in a program is compared to maximum feedrate parameter Isx98; if greater 
than this parameter, Isx98 is used instead. 

Feedrate is a magnitude and should therefore always be a positive number.  A 
negative feedrate will cause the motion to be opposite of what is defined as 
positive in the Coordinate System definition. 

Vector Feedrate Axes 

If a multi-axis move is specified by feedrate (and not time), theres is the further flexibility of specifying 
which axes control the vector feedrate using the FRAX command (on-line or buffered) and velocity is 
apportioned among these axes so that their vector combination (root of sum of squares) is the specified 
velocity.  Turbo PMAC calculates the move time as the vector distance of the feedrate axes divided by the 
programmed feedrate.  Therefore, each axis’ velocity does not have to be computed individually for each 
different angle of movement.  If a simultaneous move is requested of a non-feedrate axis, that move is 
completed in the same time as that computed for the feedrate axes.  The default feedrate axes for a 
coordinate system are the X, Y, and Z-axes. 
If there are other axes (non-feedrate axes) commanded on the same line, Turbo PMAC compares the 
move time computed for the vector feedrate axes to the move time derived by taking the greatest distance 
of a non-feedrate axis divided by the coordinate system’s alternate feedrate parameter Isx86.  Whichever 
of these move times is the longest is used for all axes. 

Example Vector Feedrate Calculations (Isx86=40) 

Vect Dist = SQRT(32 + 42) = 5 

Move Time = 5/10 = 0.5 

Vx = 3/0.5 = 6 

Vy = 4/0.5 = 8 

Vect Dist = SQRT(32 + 42) = 5 

Vect Move Time = 5/10 = 0.5 

Non-Vect Dist = 12 

Non-Vect Move Time = 12/40 = 0.3 

Vx = 3/0.5 = 6 

Vy = 4/0.5 = 8 

Vz = 12/0.5 = 24 

Vect Dist = SQRT(32+42+122)=13 

Move Time = 13/10 = 1.3 

Vx = 3/1.3 = 2.31 

Vy = 4/1.3 = 3.08 

Vz = 12/1.3 = 9.23 

Vect Dist = 0, Non-Vect Dist = 10 

Move Time = 10/40 = 0.25 

Vc = 40 

Motor Velocity Limits 

Turbo PMAC provides a velocity limit parameter Ixx16 for each Motor xx that can be used to 
automatically limit the commanded velocity in linear-mode moves even if the motion program requests a 
higher rate.  The details of how this limiting function operates are dependent on the mode of operation.