3.2 Wiring the AcuDew
The AcuDew is a 2-wire, 4-20 mA transmitter. Typical electrical connection to
generate a voltage output is shown below.
Note
: the maximum value for Rs in this circuit can be calculated by the formula:
Rs max = [40 x (Vs – 7)]Ω
If the wiring resistance is
expected to be more than a
few percent of the value of
Rs, then this resistance must
be taken away from the
answer to get the maximum
usable value of Rs.
3.3 AcuDew - Normal Operation
Note: Review the complete manual for further information if necessary.
Once the AcuDew is properly installed per the instructions contained in this
manual, use of the AcuDew moisture transmitter is extremely simple. There are no
controls to operate during normal use, as these devices are designed for long term
unattended operation. With the analogue output, connected to a data acquisition
system, recorder or process controller, the user has only to periodically monitor
the system for normal operation.
P
O
W
E
R
S
U
P
P
L
Y
+
1
2
V
t
o
+
2
8
V
4
-
2
0
m
A
S
i
g
n
a
l
+
V
s
0
V
P
i
n
1
P
i
n
2
S
E
N
S
E
R
E
S
I
S
T
O
R
S
D
T
R
s
V
o
u
t
V
o
u
t
m
a
x
=
R
s
x
2
0
x
1
0
-
3
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