Rockwell Automation 1772-LS_LSP,D17726.8.6 PROG/OPER MANUAL-MINI PLC-2/05 - Manual (Page 64)

Program Control Instructions
Chapter 7
7Ć3
If the start fence becomes:
True - Each rung condition controls their output instruction.
False - All output instructions within the zone are left in their last state. The
same outputs may now be controlled by another zone program.
Only one zone may control a set outputs at one time.
Keystrokes: You enter an MCR or ZCL instruction by performing the
following steps.
1. Press either -(MCR)- or -(ZCL)-.
Editing in a Completed Rung
You edit these instructions by performing the following steps:
1. Position the cursor over the MCR or ZCL instruction you want to change.
2. Press either -(MCR)- or -(ZCL)- or any other appropriate instruction
type key.
3. Enter any parameters that may be required by a new instruction.
Immediate I/O update instructions interrupt the program scan to update I/O data
before the normal I/O update sequence. Use these instructions where I/O
modules interface with I/O devices that operate in a shorter time period than the
processor scan.
Immediate Input/Immediate Output Update
Purpose: An Immediate Input Update instruction interrupts the program scan to
update input image table with data from the corresponding module group. The
image table is updated before the normal I/O scan and executed each program
scan (Figure 7.3). This instruction is always considered logic true and
execution takes place whether or not other rung conditions allow
logic continuity.
Immediate I/O Update
Instructions