Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 53)

Fundamental Instruction Set
Chapter 5
5Ć16
Less Than
Symbol: -|<|-
Purpose: Compares the data in your specified address with the data stored at
another address in memory. It determines the rung condition.
Syntax: Programmed after the get instruction in the condition side of the ladder
diagram rung (Figure 5.7).
Function: The rung condition becomes:
True
If the get value is less than the reference values stored in the less than
instruction.
False
If the get value is not less than the less than value.
Figure 5.7
Less Than Comparison
120
01
010
00
030
YYY
G
037
654
<
Reference Value
When YYY < 654, GET/LES comparison is true and 01000 is energized.
Get Byte
Symbol: -|B|-
Purpose: Accesses 1 byte (instead of 1 word) from one word location of the
data table.
Syntax: Can be programmed with a limit test instruction located at the
condition area of the ladder diagram (Figure 5.8). The data is shown in octal
form.
Function: Used with a put instruction to transfer either the upper or lower byte
to the lower byte of the put address.
Figure 5.8
Get Byte/Limit Test Comparison
120
06
010
00
0451
YYY
G
050
L
Reference Value
When 170 <YYY <200, comparison is true and 01005 is energized.
200
170
Limit Test
Symbol: -|L|-
Purpose: Checks to see if a byte value is between two reference byte values in
the limit test instruction.
Syntax: Programmed with a get byte instruction located at the condition area
of the ladder diagram (Figure 5.8).