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Move/Logical Instructions (MOV, MVM, BTD, MVMT, BTDT, CLR, SWPB, AND, OR, XOR, NOT, BAND, BOR, BXOR, BNOT) Chapter 7
Bit Field Distribute (BTD)
The BTD instruction copies the specified bits from the Source, shifts the bits to the appropriate position, and writes the bits into the Destination.
This instruction is available in structured text and function block as BTDT, see page 294.
Operands:
Relay Ladder
Operand
Source
Type
SINT
INT
Description
tag that contains the bits to move
DINT
A SINT or INT tag converts to a DINT value by zero-fill.
Source bit DINT immediate number of the bit (lowest bit number) from where to start the move
Destination SINT
(0-31 DINT)
(0-15 INT)
(0-7 SINT) tag must be within the valid range for the Source data type tag where to move the bits
INT
Destination bit
DINT
DINT
Format
immediate tag
Length DINT immediate
(0-31 DINT)
(0-15 INT)
(0-7 SINT) immediate
(1-32) the number of the bit (lowest bit number) where to start copying bits from the Source must be within the valid range for the
Destination data type number of bits to move
Description:
When enabled, the BTD instruction copies a group of bits from the Source to the Destination. The group of bits is identified by the Source bit (lowest bit number of the group) and the Length (number of bits to copy). The
Destination bit identifies the lowest bit number bit to start with in the
Destination. The Source remains unchanged.
If the length of the bit field extends beyond the Destination, the instruction does not save the extra bits. Any extra bits do not wrap to the next word.
If you mix integer data types, the instruction fills the upper bits of the smaller integer data types with 0s so that they are the same size as the largest data type.
Arithmetic Status Flags:
not affected
Publication 1756-RM003K-EN-P - July 2008
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291
Chapter 7 Move/Logical Instructions (MOV, MVM, BTD, MVMT, BTDT, CLR, SWPB, AND, OR, XOR, NOT, BAND, BOR, BXOR, BNOT)
Fault Conditions:
none
Execution:
Condition
prescan rung-condition-in is false rung-condition-in is true postscan
Relay Ladder Action
The rung-condition-out is set to false.
The rung-condition-out is set to false.
The instruction copies and shifts the Source bits to the Destination.
The rung-condition-out is set to true.
The rung-condition-out is set to false.
Example 1:
When enabled, the BTD instruction moves bits within value_1.
destination bit source bit
value_1
before BTD instruction
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0
value_1
after BTD instruction
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
The shaded boxes show the bits that changed in value_1.
292
Publication 1756-RM003K-EN-P - July 2008
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
Move/Logical Instructions (MOV, MVM, BTD, MVMT, BTDT, CLR, SWPB, AND, OR, XOR, NOT, BAND, BOR, BXOR, BNOT) Chapter 7
Example 2:
When enabled, the BTD instruction moves 10 bits from value_1 to value_2.
source bit
value_1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 destination bit
value_2
before BTD instruction
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
value_2
after BTD instruction
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0
The shaded boxes show the bits that changed in value_2.
Publication 1756-RM003K-EN-P - July 2008
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
293
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