Sequencers
Chapter 21
21-4
Figure 21.4
Sequencer Instructions
Key Sequence
1770T3 Display
Instruction Notes
SEQ 0
EN
SEQUENCER OUTPUT
COUNTER ADDR:
CURRENT STEP:
SEQ LENGTH:
WORDS PER STEP:
FILE:
001
1
110
DN
MASK:
010
OUTPUT WORDS
2:
3:
4:
030
17
030
15
030
001
110-
010-
1: 010
Output instruction
Increments, then transfers data.
Same data transferred each scan that the rung is true.
Counter is indexed by the instruction.
Unused output bits can be masked.
Requires 5-8 words of your program.
SEQ 1
SEQUENCER INPUT
COUNTER ADDR:
CURRENT STEP:
SEQ LENGTH:
WORDS PER STEP:
FILE:
001
1
110
MASK:
010
INPUT WORDS
2:
3:
4:
030
000
110-
010-
1: 010
Input instruction.
Compares input data with current step for equality.
Counter must be externally indexed by a counter instruction
within your program.
Unused input bits can be masked.
Requires 5-8 words of your program.
SEQ 2
EN
SEQUENCER LOAD
COUNTER ADDR:
CURRENT STEP:
SEQ LENGTH:
WORDS PER STEP:
FILE:
1
DN
LOAD WORDS
1:
2:
3:
4:
030
17
030
15
110
110-
010
001
030
000
Output instruction.
Increments, then loads data.
Counter is indexed by the instruction.
Does not mask.
Requires 4-7 words of your program.
Important:
Numbers shown are default values. Numbers in shaded areas must be replaced by user-entered values. The number of default
address digits displayed (3 or 4) will depend on the size of the data table.
Here is an explanation of each value:
This Value:
Stores the:
Counter Address
Address of the instruction in the accumulated value area of
the data table
Position
Position in the sequencer table (accumulated value of counter)
Seq Length
Number of steps (preset value of the counter)
Words per Step
Width of the sequencer table
File
Starting address of the source file
Mask
Starting address of the mask file
Word Address
Address of the source word or destination word outside of the file
Output Words
Words controlled by the instruction
Load Words
Words fetched by the instruction
Input Words
Words monitored by the instruction
