205 / 218
ELECTRO-PNEUMATIC CIRCUITS
NAND function
NOR function
P1
0 0 1
1 0 1
0 1 1
1 1 0
P2 B/1
P1
0 0 1
1 0 0
0 1 0
1 1 0
P2 B/1
P1
P1
P2
P2
x
x
X
X
B 1
B 1
Fig. 16
Figure 16
NAND function
The NAND (NOT AND) function, is only possible when a relay is present.
When relay
X
is not energized, contact
x
is
NC
therefore solenoid
B1
is energized.
The
NO
contacts of
P1
and
P2
are connected in series, when both are activated the signal passes and energizes the
coil of relay
X
, contact
x
opens and the solenoid
B1
is de-energized.
In the absence of either P1, P2 or both, B1 is energized
P1 * P2 =
B1
NOR function
The NOR (NOT OR) function is only possible in the presence of a relay.
When relay
X
is not energized, contact
x
is
NC
, solenoid
B1
is energized.
The
NO
contacts of
P1
and
P2
are connected in parallel, when either one or both are activated, the signal energizes
the coil of relay
X
, contact
x
opens and solenoid
B1
is de-energized.
In the absence of P1 and P2, B1 is energized
P1 + P2 =
B1
Figure 17
Pos. 1:
the conditions for the solenoid
B1
to be energised are:
P1
activated, the signal energizes the coil of relay
X
, which closes contact
x
and with
P2
not activated, contact
y
remains closed, the signal passes and energizes solenoid
B1
.
P1 * P2 =
B1
Pos. 2:
the conditions for the solenoid
B1
to be energised are:
P1
activated, the signal energizes the coil of relay
X
, which closes its contact
x
. In this state the position of the other
contacts have no influence.
Or
P2
activated,
P3
not activated, the signal energizes the coil of relay
Y
, which closes its contact
y
, contact
z
remains unchanged, the signal passes.
P1 + P2 + P3 =
B1
1
2
P1
P1
P2
P3
P2
x
y
x
y
z
X
Y
X
Y
Z
B 1
B 1
Fig. 17
6
203
CAMOZZI
>
ELECTRO-PNEUMATIC CIRCUITS