Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 156)

Publication 1760-UM001D-EN-P - September 2005
7-6 Retention
Impulse Relay
Task:
After a power failure, the lights in a stairwell should resume their
previous state.
Contacts and relays used:
Signal diagram:
U = Supply voltage
Range A: Q1 was on prior to losing power. When power is re-applied
and the T2 timer expires, Q1 turns back on.
Range B: Q1 was on prior to losing power. When power is re-applied,
switch I1 is on, so Q1 stays off. Use time T2 to avoid brief flicker.
Range C: M15 is switched on and remains set until the next time I1 is
activated.
Coil Function
T2 Enable after first cycle
I1 Push-button
Q1 Lamp output
M15 Impulse relay (retentive)
-----------TT2
I1-------- M15
M15-T2-----{Q1
00.10
TRG
RES
X
S
{ T2
+
Circuit Diagram: Parameter Display:
U
I1
M15
Q1
T2
t t t
A B C