Introduction to Programming
Chapter 4
47
by an Output Unlatch instruction. If power is lost and back-up battery for
CMOS RAM memory is maintained, all latched bits will remain on.
The Output Unlatch instruction is used to de-energize a memory bit
that has been latched on. The Output Unlatch instruction addresses the
same memory bit that has been latched on (Figure 4.8). When the rung
conditions for the Output Unlatch instruction go true, the addressed
memory bit is reset to zero (off) (Figure 4.9). The output unlatch is also
retentive. This means that once the rung conditions go false, the unlatched
bit remains off.
Figure 4.8
Latch/Unlatch
Instructions
||
04
(
L )
00
113 010
||
05
( U )
00
113 010
Figure 4.9
Latch/Unlatch
T
iming Diagram
True
False
True
False
On
Off
ÇÇÇÇÇÇÇÇ
ÇÇÇÇÇÇÇÇ
Latch
Rung
Unlatch
Rung
Output
Bit
01000
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
To Next Page
Loading...
Need help?
General
