Rockwell Automation 1771-QB Linear Pos. - Manual (Page 153)

Sample Application Programs
Chapter 10
10Ć9
Rung 2:1
Rungs 2:1, 2:2, and 2:3 determine which block (parameter, setpoint, or
command) will be sent to the module via the next block transfer write (BTW). If
the axis 1 ready bit is low, (the module is in powerup or a reset command has
just been executed), rung 2:1 moves the source address of the parameter block
into the BTW’s control block. This causes the programmable controller to send
the parameter block when rung 2:4 is executed.
Rung 2:2
If the ready bit is high and the setpoints received bit is low (the module has
received a valid parameter block but has not yet received a setpoint block), rung
2:2 moves the source address of the setpoint block into the BTW’s control
block. This causes the programmable controller to send the setpoint block when
rung 2:4 is executed.
Rung 2:3
If the ready bit and the setpoints received bit are high, (the module has received
a valid parameter block and the setpoint block), rung 2:3 moves the source
address of the command block into the BTW’s control block. This causes the
programmable controller to send the command block when rung 2:4 is
executed.
Rung 2:4
Rung 2:4 writes the block selected by rung 2:1, 2:2, or 2:3 to the module.
Rung 2:5
Rung 2:5 controls the order of axis 1 moves and issues the start command for
the move. When axis 1’s in-position bit goes high, the sequencer alters control
word 2 in the command block to indicate the next setpoint and the rung issues
the start command. When the next BTW occurs (sends the altered command
block), the next setpoint movement profile begins executing and the in-position
bit goes low again.