Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 123)

Publication 1760-UM001D-EN-P - September 2005
Draw a Circuit Diagram with Pico 4-63
On the first pass, the value is switched on once by break contact M9.
If Q1 is set, M9 is switched on. Each output is turned on and off in
sequential order (i.e. Q1, Q2, Q3, Q4). Pico changes state every
second. Once Q4 (the last storage position) has been switched on, the
value is passed back to Q1.
Stairwell Lighting
To save electricity, building maintenance wishes to keep the lights in a
stairwell turned off unless someone is using the stairwell. The
following program turns on the lights in the stairwell when a push
button switch is pressed and released. Pressing the push button a
second time turns off the lights. If the lights are not turned off
manually, the Pico program turns them off after 6 minutes. If the push
button is held for more than 2 seconds, the lights stay on continuously
until someone presses the push button again.
The enhanced version of this program turns the lights off again after 4
hours if the push button was held for more than 2 seconds rather than
leaving them on indefinitely.
-----------TT1
T1-M7------{M8
--------{M7
Q1---------SM9
M8-Q3------SQ4
Q4------RQ4
Q2------SQ3
Q3------RQ3
Q1------SQ2
Q2------RQ2
Q4------SQ1
M9
Q1------RQ1
Flasher Relay
Generate shift pulse
Clear first value
Set 4th storage position
Set 3rd storage position
Set 2nd storage position
Set 1st storage position
Enter first value (=1)
Clear 4th storage position
Clear 3rd storage position
Clear 2nd storage position
Clear 1st storage position