Delta MS300 Series User Manual page 691

Chapter 16 PLC Function ApplicationsMS300
Example 8: Flashing circuit
The following diagram shows an oscillating circuit of a type commonly used to cause an
indicator to flash or a buzzer to buzz. It uses two timers to control the ON and OFF time
of Y1 coil. Here constants n1 and n2 are the setting values of timers T1 and T2, and T is
the clock cycle of the timer.
Example 9: Triggering circuit
In the diagram below, a rising edge in input X0 causes coil M0 to generate a single pulse
for ΔT (length of one scanning cycle), and coil Y1 is electrified during this scanning
cycle. Coil M0 loses power during the next scanning cycle, and N.C. contact M0 and
N.C. contact Y1 are both closed. This causes coil Y1 to stay in an electrified state until
there is another rising edge in input X0. This again causes the electrification of coil M0
and the start of another scanning cycle, while also causing coil Y1 to lose power, and so
on. You can see the sequence of these actions in the diagram below. This type of circuit
is commonly used to enable one input to perform two alternating actions. You can see
from the time sequence in the diagram below that when input X0 is a square wave signal
with a period of T, the output of coil Y1 is a square wave signal with a period of 2T.
Example 10: Delay circuit
When input X0 is ON, because the corresponding NC contact is OFF, the timer T10 is in
a no power state, and output coil Y1 is electrified. T10 receives power and begins to
counter the time only after input X0 is OFF, and output coil Y1 is delayed for 100
seconds (K1000 × 0.1 sec. = 100 sec.) before losing power. You can see the sequence
of actions in the diagram below.
X0 T2
TMR T1
T1
TMR T2
X0 T1
Y1
Kn1 X0
Kn2
Y1
n1*T
Figure 16-45
Figure 16-46
Figure 16-47
682
n2*T