Rockwell Automation D64046.5.1 U MNL WIN DDMC - Manual (Page 16)

Chapter 1
Understanding How a DDMC32 System Works
1-4
Sample Step Configuration Template With SDS Instruction
STEP 1 READY TIMER=0.0s – DISABLED MSG:OFF
No Input ID Equation Destination No Output ID State
0 RET’D LS OFF––>ON STEP 0 0 FORWARD MOTOR 1 OFF
1 ADV’D LS OFF––>ON STEP 10 1 REVERSE MOTOR 1 OFF
2 FULL DEPTH LS OFF––>ON STEP 0 2 DRILL MOTOR OFF
3 ADVANCE COMMAND OFF––>ON **STEP 2
4 RETURN COMMAND
Press a function key.
Program edit mode PLC–5/25 Addr 1
Display Step Step Edit Step Msg Input Output Marked
Symbol Name Type Step Timer On Transit State Exit
F2 F3 F4 F5 F6 F7 F8 F9 F10
How the Transitional SDS Instruction Handles Inputs
Transitional equations provide state-based control. Each transitional
equation defines the destination step based on the transition of a particular
input (ON ––> OFF or OFF ––> ON). When input state transition
conditions are used, the expected input states appear on the left side of the
equation column and the transition states on the right. The destination
column is on the right of the equation column (see the figure above).
At power up, the SDS instruction starts out in an “initialized” step. The
instruction searches through each defined step to find a match based on the
expected states of inputs. If it cannot find a match, the SDS instruction
looks for a set of conditions defined by a combinatorial equation (see the
figure on page 1-5). If a transition is specified, you must validate the
entry state or you will not see a transition and will be locked into a step.
Because all input states in each step may be important, you must consider
the logical progression of I/O sequencing when developing a step
configuration. These considerations differ from those you make with
traditional ladder logic, as the sequence of I/O changes are not relevant.