Automationdirect.com DirectLOGIC DL205 Series User Manual page 371

Chapter 5: Standard RLL Instructions - Table
Table to Destination (TTD)
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The Table To Destination instruction moves a value from a
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V-memory table to a V-memory location and increments the
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table pointer by 1. The first V-memory location in the table
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250-1
contains the table pointer which indicates the next location in
260 the table to be moved. The instruction will be executed once
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per scan provided the input remains on. The table pointer will
reset to 1 when the value equals the last location in the table.
DS Used
The function parameters are loaded into the first level of the
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HPP Used
accumulator stack and the accumulator by two additional
instructions. Listed below are the steps necessary to program
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the Table To Destination function.
Step 1: Load the length of the data table (number of V-memory locations) into the first level of the
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Step 2: Load the starting V-memory location for the table into the accumulator. (Remember, the
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Step 3: Insert the TTD instruction which specifies destination V-memory location (Vaaa).
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Helpful hint: — For parameters that require HEX values when referencing memory locations,
the LDA instruction can be used to convert an octal address to the HEX equivalent and load
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the value into the accumulator.
Helpful hint: — The instruction will be executed every scan if the input logic is on. If you do
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not want the instruction to execute for more than one scan, a one shot (PD) should be used
in the input logic.
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Helpful hint: — The pointer location should be set to the value where the table operation
will begin. The special relay SP0 or a one shot (PD) should be used so the value will only be
set in one scan and will not affect the instruction operation.
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13
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Discrete Bit Flags
SP53
A
NOTE: Status flags (SPs) are only valid until:
— another instruction that uses the same flag is executed, or
B
— the end of the scan.
C
The pointer for this instruction starts at 0 and resets when the table length is reached. At first glance it may
appear that the pointer should reset to 0. However, it resets to 1, not 0.
D
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DL205 User Manual, 4th Edition, Rev. B
accumulator stack. This parameter must be a HEX value, 0 to FF.
starting location of the table is used as the table pointer.) This parameter must be a HEX
value.
Operand Data Type
V-memory
On if there is no value in the table that is equal to the search value.
DL260 Range
aaa
V All (See page 3 - 56)
Description
TTD TTD
V aaa aaa