Allen-Bradley MicroLogix 1200 Reference Manual page 206

15-6 Sequencer Instructions
Word
B10:1
B10:2
B10:3
B10:4
B10:5
Publication 1762-RM001C-EN-P
If the position is equal to zero at start-up, when you switch the controller
from the program mode to the run mode, the instruction operation
depends on whether the rung is true or false on the first scan.
• If the rung is true, the instruction transfers the value in step zero.
• If the rung is false, the instruction waits for the first rung transition
from false-to-true and transfers the value in step one.
The bits mask data when reset (0) and pass data when set (1). The
instruction will not change the value in the destination word unless you
set mask bits.
The mask can be fixed or variable. It is fixed if you enter a hexadecimal
code. It is variable if you enter an element address or a file address (direct
or indirect) for changing the mask with each step.
The following figure indicates how the SQO instruction works.
Destination O:14.0
15 8 7
0000 0101 0000 1010
Mask Value 0F0F
15 8 7
0000 1111 0000 1111
Sequencer Output File #B10:1
0000 0000 0000 0000
1010 0010 1111 0101
1111 0101 0100 1010
0101 0101 0101 0101
0000 1111 0000 1111
SQO SQO
Sequencer Output EN
File #B10:1
Mask 0F0F DN
Dest O14:0
Control R6:20
Length 4<
Position 2<
External Outputs (O:14)
at Step 2
0
0
Step
0
1
2 Current Step
3
4
00
01 ON
02
03 ON
04
05
06
07
08 ON
09
10 ON
11
12
13
14
15