4-6
IM CA150E
4.3.3 20 mA SINK Function
The SINK function allows you to use DC current (DCA) with the polarity
set to - (minus). This allows drawing (SINK) the specified value of
the current from an external voltage source (distributor, etc.) in
the direction of the H terminal. Thus, you can use the instrument in a loop test,
for example, as a simulator for two-wire transmitters.
CAUTION
Use the external power supply of 20 mA SINK within the 5 to 28 V range.
Set the polarity of the applied voltage as shown in the figure below and
take care not apply a voltage in the opposite direction.
MEASURE
CA150
SOURCE
24V DC
AC or DC
power supply
Output 1-5 V
4-20 mA
+
-
Distributor
H L mA
H L
1
Use the FUNCTION key on the SOURCE side to align
the
source mark with DCA. (DC current selection)
2
Use the RANGE key to select the 20 mA range.
(-22.000 mA to 22.000 mA)
3
Use the ▲ ▼ output value setting keys to set each digit output value.
Each ▲ ▼ key corresponds to a digit of the setting value.
Each time a key is pressed the value is incremented or decremented by
one count. If you attempt to increment or decrement
the value 9 or 0, the digit moves up or down one place.
A value continues to change when you hold down the key.
Press the CLEAR key to restore the setting to its initial value (zero).
4
Use the + ← → - key to set the polarity to minus.
5
Connect the terminals as shown in the figure above.
6
Turn on the power of the external voltage source (distributor).
Press the SOURCE ON/OFF key to start generation.
(SOURCE OFF changes to ON.)
7
Press the SOURCE ON/OFF key again to turn off the output.
(OFF lights and the output terminals are open-circuited.)
Tip
The I/O signals of the distributor can be checked by connecting the terminals
as indicated by the dashed line in the figure above.
4.3 Source DC Current (DCA) Signals
