DL205 Analog Manual, 7th Edition Rev. D
16-22
Chapter 16: F2-8AD4DA-2, 8-Ch. In / 4-Ch. Out Analog Voltage Combination
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
C
D
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
C
D
Scaling the Input Data
Most applications require measurements in engineering units, which provide more meaningful
data. For input ranges with a minimum value of zero, this can be accomplished by using the
conversion formulas shown below.
EU = (A)(EU
H
- EU
L
) / (A
max
)
EU = (D)(EU
H
- EU
L
) / (D
max
)
•
A = analog value from current transmitter
•
D = digital value of input provided to PLC CPU
•
EU = engineering units
• EU
H
= engineering units high value
• EU
L
= engineering units low value
The following examples show a 16 bit measurement of pressure (PSI) from 0.0–140.0. The
the analog value needs to be multiplied by 10 in order to imply a decimal place when the
value is viewed with the programming software. Notice how the calculations differ when the
multiplier is used.
Scaling Example
NOTE: Binary data format is recommended for 14 or 16 bit resolution input data, especially if the input
data is to be used in any math instructions (DL205 User Manual, ch.5). There is only one V-memory word
(16 bits) available for the actual data. Although the 12 bit resolution maximum value of 4095 can be stored
in one word using either binary or BCD formats, the 14 and 16 bit resolution maximum values of 16383 and
65535 both exceed the BCD format’s maximum single word capacity of 9999. Double word math would be
required for 14 or 16 bit data in BCD format. Binary data format is also useful for displaying data on some
operator interfaces.
Analog Value of 6.3V, 0–10V transmitter, 16 bit resolution, should yield 88.2 PSI
EU
=
(D) EU
H
−
EU
L
D
max
EU
=
(41287) 140
−
0
65535
EU
=
88
EU
=
(10)(D) EU
H
−
EU
L
D
max
EU
=
(10)(41287) 140
−
0
65535
EU
=
882
Example without multiplier
Example without multiplier
Summary of Contents for DL205
Page 1: ...DL205 Analog I O Manual Manual Number D2 ANLG M ...
Page 2: ...Notes ...
Page 6: ...Notes ...