Analog Data Bits; Module Resolution - Automation Direct DL405 User Manual

16–10
F4–16DA–1 16-Ch. Analog Current Output
Analog Data
Bits
Module
Resolution
The first twelve bits of both V-memory
locations represent the analog data in
binary format.
Bit Value Bit
0 1
1 2
2 4
3 8
4 16 10
5 32 11
Since the module has 12-bit resolution,
the analog signal is made of 4096 counts
ranging from 0 – 4095 (2
20 mA scale, sending a 0 produces a 4
mA signal, and 4095 gives a 20 mA
signal. This is equivalent to a binary
value of 0000 0000 0000 to 1111 1111
1111, or 000 to FFF hexadecimal. The
graph to the right shows the linear
relationship between the data value and
output signal level.
Each count can also be expressed in
terms of the signal level by using the
equation shown. The following table
shows the smallest signal change that
occurs when the digital value is
increased by 1 LSB.
Signal Range
4 to 20mA
MSB
1 1
Value
5 4
6 64
7 128
8 256
9 512
1024
2048
MSB
1 1
5 4
20mA
12
). For the 4 to
4mA
Resolution + H * L
H = high limit of the signal range
L = low limit of the signal range
Span Divide By
(H – L)
16mA
V40501
1 1 1 1 9 8 7 6 5 4 3 2 1
3 2 1 0
– data bits,
channels 1 through 8
V40502
1 1 1 1 9 8 7 6 5 4 3 2 1
3 2 1 0
– data bits,
channels 9 through 16
0 4095
4095
Smallest Change
3.91 mA
4095
LSB
0
LSB
0