DL205 Analog Manual, 7th Edition Rev. D
6-15
Chapter 6: F2-04RTD 4-Channel RTD Input
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A
B
C
D
Negative Temperatures 2’s Complement for the DL240, DL250-1 and DL260
CPUs (Binary/Pointer Method)
The 2’s complement mode used for negative temperature display purposes, while at the
same time using the magnitude plus sign of the temperature in a control program. The
Direct
Soft element Signed Decimal is used to display negative numbers in 2’s complement
form. To find the absolute value of a negative number in 2’s complement, invert the number
and add 1 as shown in the following example:
Understanding the Input Assignments (Multiplexing Ladder Only)
Remember that this module appears to the CPU as a 32-point discrete input module. Use
these points to obtain:
•
An indication of which channel is active
•
The digital representation of the analog signal
•
Module diagnostic information
Since all input points are automatically mapped into V-memory, it is easy to determine the
location of the data word that will be assigned to the module.
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A
b
C
D
LD
V2000
OUT
V2010
ADDB
K1
V2000
K8000
²
INV
Load negative value into the accumulator so we
can convert it to a positive value.
Invert the binary pattern in the accumulator.
Add 1.
Save Channel 1 data at V2010.
Repeat for other channels as required.
F2-04RTD
V40400
V40403
8pt
Input
8pt
Input
16pt
Input
Output
16pt
32pt
Input
X0
--
X7
X10
--
X17
X20
--
X57
X60
--
X77
Y0
--
Y17
Slot 0
Slot 1
Slot 2
Slot 3
Slot 4
X
3
7
V40401
B
S
L
B
S
M
X
2
0
X
2
7
X
3
0
X
5
7
V40402
B
S
L
B
S
M
X
4
0
X
4
7
X
5
0
0
1
3
4
5
6
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14
2
5
1
Bit
0
1
3
4
5
6
7
8
9
10
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12
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14
2
5
1
Bit
Summary of Contents for DL205
Page 1: ...DL205 Analog I O Manual Manual Number D2 ANLG M ...
Page 2: ...Notes ...
Page 6: ...Notes ...
