DL205 User Manual, 4th Edition, Rev. B
5–52
Chapter 5: Standard RLL Instructions - Timer, Counter and Shift Register
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
Shift Register (SR)
The Shift Register instruction shifts data through a
predefined number of control relays. The control ranges in
the shift register block must start at the beginning of an 8
bit boundary and use 8-bit blocks.
The Shift Register has three contacts.
• Data — determines the value (1 or 0) that will enter the
register
• Clock — shifts the bits one position on each low to high
transition
• Reset —resets the Shift Register to all zeros.
With each off to on transition of the clock input, the bits which make up the shift register
block are shifted by one bit position and the status of the data input is placed into the starting
bit position in the shift register. The direction of the shift depends on the entry in the From
and To fields. From C0 to C17 would define a block of sixteen bits to be shifted from left to
right. From C17 to C0 would define a block of sixteen bits, to be shifted from right to left.
The maximum size of the shift register block depends on the number of available control
relays. The minimum block size is 8 control relays.
SR
aaa
From A
bbb
To B
DATA
CLOCK
RESET
Data Input
Clock Input
Reset Input
Shift Register Bits
C0
C17
Reset
1
1
0
0
1
0
0
1
0
1
1
0
0
1
0
0
0
1
Inputs on Successive Scans
X1
X2
SR
C0
From
C17
X3
To
Handheld Programmer Keystrokes
Direct
S
O
FT
STR
$
1
B
EN
T
STR
$
2
C
STR
$
3
D
SHFT
EN
T
EN
T
RST
S
O
R
N
R
SHFT
0
A
1
B
7
H
EN
T
SHFT
Indicates
ON
Indicates
O
FF
Clock
Data
þ
þ
þ
þ
230
240
250-1
260
Operand Data
Type
DL230 Range
DL240 Range
DL250-1 Range
DL260 Range
A/B
aaa
bbb
aaa
bbb
aaa
bbb
aaa
bbb
Control Relay C
0-377
0-377
0-377
0-377
0-1777
0-1777
0-3777
0-3777
DS
Used
HPP Used
