Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 160)

Publication 1760-UM001D-EN-P - September 2005
7-10 Retention
Contacts and relays used:
I2 and I3 are converted to one-shot pulses by T6 / T7. Only the
actuation of the push-button is recognized. Should they remain
constantly pressed, malfunctions would occur.
In the above example,
T7 does not have to be retentive.
I2 is a normally open push button, and I3 is a normally closed push
button. A normally closed push button is used for the STOP
CONVEYOR signal so that in the event of a loose or broken wire, the
conveyor automatically stops.
Signal diagram:
U = Supply voltage
The make contact of T8 closes for one Pico cycle and resets M16, Q1.
Coil Function
T6/T7 One shot timers
I2 Start conveyor belt
Q1 Conveyor belt motor
I3 Stop conveyor belt
M16 Stop selected
T8 Remaining time
I2---------TT6
T6---------SQ1
M16
I3----------TT1
T1---------SM16
M16---------TT8
T8----------RQ1
RM16
30.00
TRG
RES
T8
+
X
S
{
Circuit Diagram: Parameters Entered:
Time setting for T6, T7
U
I2/T6
Q1
I3
M16
T8
t
1
t
2
t + t = 30s
1 2