Rockwell Automation 1760-xxxx Pico Controller User Manual - Manual (Page 167)

Publication 1760-UM001D-EN-P - September 2005
Retention 7-17
Function of the Pico circuit
diagram:
T1 provides the clock pulse.
When a time of t = 0.5 seconds
is selected the counting period
amounts to 2 x t = 1 s. One
pulse is counted every second.
The up counter C8 switches
valve Q1 on via M15 at 3600
counting pulses (3600 s = 1 h).
M15 resets C8 and prepares C8
for the next hour. To stop C8
from continuing to count while
lubrication is in process, the
break contact of M15 blocks
the counting of pulses.
T8 is actuated by means of
M15. Once T8 has timed out,
M15 and T8 will be reset.
In order that both the time elapsed since the last lubrication (counter
C8) and also the lubrication pulse remains constant in the event of a
power outage, C8, M15 and T8 must be retentive.
-----------TT1
T1-M15-----CC8
C8--------SM15
M15--------TT8
RC8
M15-T8-----{Q1
T8--------RM15
00.50
TRG
RES
T1
+
{
S
3600
DIR
CNT
RES
C8
+ {
{
T8
+ RES
30.00
TRG
X
S
{
Circuit Diagram:. Parameters entered:
Parameter Display:
Parameters entered: