Automation Direct DL405 User Manual page 384

Output Enable Output bit 15 is the Output Enable
Bit control bit for all eight channels. When
the bit is off, all eight channel output
voltage levels drop to 0VDC. Disabling
the outputs also clears all eight output
data registers. To resume analog output
levels, first the Output Enable control bit
must turn on. Then, the CPU must write
new data to each channel to restore the
output voltage for that channel.
Analog Data Bits The first twelve bits of the data word
represent the analog data in binary
format.
Bit
0
1
2
3
4
5
Module Since the module has 12-bit resolution,
Resolution the analog signal is made of 4096 counts
ranging from 0–4095 (2
5V scale, sending a 0 produces a 0VDC
signal, and 4095 sends a 5VDC 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
increased by 1 LSB.
Value Bit
1 6
2 7
4 8
8 9
16 10
32 11
12
when the digital value is
Signal Range
0 to 5VDC
0 to 10VDC
F4–08DA–2 8-Ch. Analog Voltage Output
MSB
1 1 1
5 4 3
MSB
1 1 1
Value
5 4 3
64
128
256
512
1024
2048
5VDC or
10VDC
). For the 0 to
0VDC
Resolution + H * L
H = high limit of the signal range
L = low limit of the signal range
Span Divide By
(H – L)
5VDC 4095
10VDC 4095
V40501
LSB
1 1 1 9 8 7 6 5 4 3 2 1
2 1 0
– Output Enable Bit
OFF = Disable (and clear)
ON = Enable
V40501
LSB
1 1 1 9 8 7 6 5 4 3 2 1
2 1 0
– data bits
0 4095
4095
Smallest Change
1.221mV
2.442mV
19–9
0
0