α
2 Simple Application Controllers
The Logic Function Blocks 5
5 - 1
5.
The Logic Function Blocks
Logic Function Blocks operate by reading whether signals are ON or OFF and then setting the
status of their Outputs accordingly. There are six types of logic blocks available in the
α
2
Series - AND, OR, NAND, NOT, NOR, XOR. Analog signals cannot be processed by the Logic
blocks. In this chapter, each Function Block has a description, a diagram of the Function Block
as seen on the LCD Display, and a logic table to show how the Output is controlled by the input
signals.
Table 5.1: Boolean Logic function blocks
Logic
Block
State
Logic Block
Displayed
Description
Memory
Use
Section
Reference
AND
T h i s f u n c t i o n exe c u t e s l o g i c a l A N D
operation on given input signals. The input
signals connected should be of bit input
type only. 4 Bit input pins and 1 Bit output
pin. If all the inputs are ON then the output
is ON, otherwise output is OFF.
19 Byte
5.1
OR
This function executes logical OR operation
on given input signals. The input signals
connected should be of bit input type only. 4
Bit input pins and 1 Bit output pin. If all the
i n p u t s a r e O F F t h e n o u t p u t i s O F F,
otherwise output is ON.
19 Byte
5.2
NOT
This function executes logical NOT opera-
tion on given input signal. The input signal
connected should be of bit input type only. 1
Bit input pin and 1 Bit output pin. Output is
negation of Input given.
10 Byte
5.3
XOR
This function executes logical XOR opera-
tion on given input signals. The input sig-
nals connected should be of bit input type
only. 2 Bit input pins and 1 Bit output pin.If
both the inputs are either OFF or ON then
out put is OFF, otherwise output is ON
13 Byte
5.4
NAND
Th i s f un c t i o n exe c u te s l o g i c al N A ND
operation on given input signals. The input
signals connected should be of bit input
type only. 4 Bit input pins and 1 Bit output
pin. If all the inputs are ON then output is
OFF, otherwise output is ON
19 Byte
5.5
NOR
This function executes logical NOR oper-
ation on given input signals. The input sig-
nals connected should be of bit input type
only. 4 Bit input pins and 1 Bit output pin. If
all the inputs are OFF then out put is ON,
otherwise output is OFF
19 Byte
5.6
0 0
A N D
2
3
O
4
1
0 0
O R
2
3
O
4
1
0 0
N T
1
O
0 0
X O R
1
2
O
0 0
N A N D
2
3
O
4
1
0 0
N O R
2
3
O
4
1
