Omron CQM1H - PROGRAM Programming Manual page 257

Step Instructions: STEP DEFINE and STEP START–STEP(08)/SNXT(09)
00000
00001
00002
Address Instruction
00000 LD
00001 SNXT(09)
00002 STEP(08)
Step controlled by LR 1500.
00100 LD
00101 SNXT(09)
Precautions
232
be used at different locations before the step to control the step according to
two different execution conditions (see example 2, below). Any step in the pro-
gram that has not been started with SNXT(09) will not be executed.
Once SNXT(09) is used in the program, step execution will continue until
STEP(08) is executed without a control bit. STEP(08) without a control bit
must be preceded by SNXT(09) with a dummy control bit. The dummy control
bit may be any unused IR or HR bit. It cannot be a control bit used in a
STEP(08).
Execution of a step is completed either by execution of the next SNXT(09) or
by turning OFF the control bit for the step (see example 3 below). When the
step is completed, all of the IR and HR bits in the step are turned OFF and all
timers in the step are reset to their SVs. Counters, shift registers, and bits
used in KEEP(11) maintain status. Two simple steps are shown below.
Step controlled by LR 1500
Step controlled by LR 1501
Operands
00000
LR 1500
LR 1500
00001
LR 1501
Steps can be programmed in consecutively. Each step must start with
STEP(08) and generally ends with SNXT(09) (see example 3, below, for an
exception). When steps are programmed in series, three types of execution
are possible: sequential, branching, or parallel. The execution conditions for,
and the positioning of, SNXT(09) determine how the steps are executed. The
three examples given below demonstrate these three types of step execution.
Interlocks, jumps, SBN(92), and END(01) cannot be used within step pro-
grams.
Bits used as control bits must not be used anywhere else in the program
unless they are being used to control the operation of the step (see example
3, below). All control bits must be in the same word and must be consecutive.
Starts step execution
SNXT(09) LR 1500
STEP(08) LR 1500
SNXT(09) LR 1501
STEP(08) LR 1501
SNXT(09) LR 1502
STEP(08)
Ends step execution
Address Instruction Operands
00102 STEP(08) LR
Step controlled by LR 1501.
00200 LD
00201 SNXT(09) LR
00202 STEP(08) ---
Section 5-15
1st step
2nd step
1501
00002
1502