Rockwell Automation 1771-QB Linear Pos. - Manual (Page 142)

Advanced Features
Chapter 9
9-11
Desired Position, Local Velocity, Local Acceleration and Local
Deceleration Words
The format of the (MS) desired position, (LS) desired position, local
velocity, local acceleration and local deceleration words in the motion
block (see Figure 9.1) is the same as the format of the (MS) setpoint
position, (LS) setpoint position, local velocity and local deceleration words
in the setpoint block.
Trigger Velocity/Position Words
If you specify a position or velocity trigger, in control word 2 you must
specify a corresponding position or velocity in the trigger velocity/position
words. If neither a velocity nor position trigger is specified in control word
2, the trigger velocity/position words are ignored. The data format for the
position and velocity words is the same as the format for the (MS) setpoint
position, (LS) setpoint position and local velocity, in the setpoint block.
Important: The module interprets all velocities as magnitudes without
positive or negative direction. Therefore, a velocity trigger condition will
be satisfied when the current velocity magnitude (axis moving in either
direction) crosses the specified trigger velocity magnitude.
Bits 0 to 6 of axis control word 2 in the command block are used to
identify the next setpoint or motion block you want to command. To
initiate a motion block movement, you command one of its motion
segments by placing the motion segment ID in bits 0 to 6. A motion
segment ID number can be from 14 to 127 in binary format. (See
Figure 7.45.)
Status word 2 will indicate when motion segments are active (see
Figure 6.4) while the extended status words 10 and 11 will contain the ID
number of the active motion segment (see Figure 6.8). Any programming
errors in the motion blocks or any operational errors that occur while using
motion segments will be reported in words 4, 5 and 8, 9 of the status block
(see Figure 6.5 and Table 6.A) if those words are configured by the
command block to return diagnostics.
The Command Block and the
Motion Block
The Status Block and the
Motion Block