Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 160)

Special Programming Techniques
Chapter 11
11Ć13
When bit 11204 goes true, bit 01114 is latched on. As soon as bit 11204 makes
a true-to-false transition, the one-shot bit (bit 25300) is set on and bit 01114 is
unlatched. Bit 15300 will remain on for only one scan. The input bit 11204
must make a false-to-true transition then a true-to-false transition to set the
one-shot bit for another scan.
You can control start-up manually when using the EPROM back-up memory.
Anytime that an EPROM to RAM memory transfer occurs, bit 02701 in the data
table will be reset by the processor. This allows a machine’s start switch to be
programmed in either of two ways as shown in Figure 11.6 and Figure 11.7.
The technique shown in Figure 11.6 can be used when your program does not
contain any MCR instruction. The technique shown in Figure 11.7 is an
alternative if an unused octal identifier (chapter 6 section B) is available.
Figure 11.6
Manual Restart Using a JMP Instruction
START 027
01
027
01
06
JMP
06
LBL
Figure 11.7
Manual Restart Using an MCR Instruction
START 027
01
027
01
MCR
MCR
Manual Restart