Step Transitions; Drum Instruction Types; Timer-Only Transitions - Automation Direct DL05 User Manual

Chapter 6: Drum Instruction Programming

Step Transitions

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Drum Instruction Types

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There are two types of Drum instructions in the DL05 CPU:
• Timed Drum with Discrete Outputs (DRUM)
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• Time and Event Drum with Discrete Outputs (EDRUM)
The two drum instructions include time-based step transitions, and the EDRUM includes
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event-based transitions as well. Each drum has 16 steps, and each step has 16 outputs. Refer
to the figure below. Each output can be either a Y or C coil, offering programming flexibility.
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We assign Step 1 an arbitrary unique output pattern.

Timer-Only Transitions

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Drums move from one step to another based on time and/or an external event (input). Each
step has its own transition condition which you assign during the drum instruction entry. The
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figure below shows how timer-only transitions work.
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The drum stays in Step 1 for a specific duration (user-programmable). The timebase of the
timer is programmable, from 0.01 seconds to 99.99 seconds. This establishes the resolution,
or the duration of each "tick of the clock". Each step uses the same timebase, but has its own
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unique counts per step, which you program. When the counts for Step 1 have expired, then
the drum moves to Step 2. The outputs change immediately to match the new pattern for
B
Step 2.
The drum spends a specific amount of time in each step, given by the formula:
C
D
6–4
DL05 Micro PLC User Manual, 6th Edition, Rev. A
Step 1 Outputs:
Increment
count timer
No Has counts per
step
expired?
Yes
Step 2 Outputs:
Use next transition criteria
Time in step = 0.01 seconds X Timebase x Counts per step