Eaton ELC-PB, Programming Manual

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3 . I n s t r u c t i o n S e t
M N050 03003E F or mo re infor ma tio n vi sit:
w w w. e a t o n . c o m
3-91
API Mnemonic Operands Function
38 SFWR P
S, D, n
Shift Register Write
Bit Devices Word devices Program Steps
Type
OP
X Y M S K H KnX KnY KnM KnS T C D E F
S * * * * * * * * * * *
D * * * * * *
n * *
SFWR, SFWRP: 7 steps
ELC ELCB ELCM
PB PC/PA/PH PV PB PH/PA
32 16 P 32 16 P 32 16 P 32 16 P 32 16 P
Operands:
S
: Source address
D
: Starting address of data stack
n
: Length of data stack
Description:
1. This instruction defines the data stack of
n
words starting with
D.
This first address of the
data stack is the pointer into the remainder of the data stack. When D=1, the value of S is
moved into position 1 of the data stack (when the instruction is executed the first time). D is
incremented with each execution of the instruction and should be reset when it reaches the
last element of the data stack. When the contents of the pointer (D) exceeds
n-1
, the
instruction stops and carry flag M1022= ON.
2. This instruction works best with the pulse instruction (SFWRP).
3. Valid range of operand
n
: 2 ≤
n
≤ 512
Program Example:
1. First, X20=ON resets the contents of D0 to 0. When X0 goes from OFF to ON, the contents
of D0 becomes 1 and the contents of D20 is moved into D1. After changing the content of
D20, X0 goes from OFF to ON again, then the contents of D0 becomes 2 and the contents of
D20 is moved into D2.
2. Please refer to the following n ~ o steps to perform SFWR instruction.
n The content of D20 is created and built in D1.
o The content of D0 becomes 1.
X20
RST D0
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
D20
X0
SFWRP D20 K10 D0
Reset the content of D0 to 0 (zero) previously
Pointer
n = 10 points
D0 = 3 2 1
Point to note:
The API 38 SFWR instruction can be used with the API 39 SFRD instruction create a first-in,
first-out (FIFO) application.