Rockwell-automation 1772-LV Mini-PLC - 2/15 Programmable Controller (S Manual de usuario descargar pdf (Pagina 160)

Special Programming Techniques

Chapter 11

1113

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

JMP

LBL

Figure 11.7

Manual Restart Using an MCR Instruction

START

027

MCR

Manual Restart

1 2 ... 155 156 157 158 159 160 161 162 163 164 165 ... 214 215

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Rockwell-automation 1772-LV Mini-PLC - 2/15 Programmable Controller (S Manual de usuario Pagina 160