Automation Direct DL405 User Manual page 53

3–10
F4–04AD 4-Channel Analog Input
By changing the wiring slightly and adding an external resistor to convert the
current to voltage, you can easily adapt this module to meet the specifications for a
transmitter that does not adhere to one of the standard input ranges. The following
diagram shows how this works.
Field wiring
(external to module)
+
50mA
Current
Generated
transmitter
voltage
–
V
max
R =
I
max
R = value of external resistor
V = high limit of selected voltage range (5V or 10V)
max
I = maximum current supplied by the transmitter
max
Example: current transmitter capable of 50mA, 0-10V range selected.
10V
R = R = 200 ohms
50mA
NOTE: Your choice of resistor can affect the accuracy of the module. A resistor that
has $0.1% tolerance and a $50ppm/_C temperature coefficient is recommended.
(internal equivalent circuit)
Current flow
V
I
250 ohms
R
C
0V
Module
High impedance
0V
High impedance