Source
4-7
IM CA150E
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App
Input Inductance Component
• The current source function of the instrument may result in an unstable
output if the instrument is connected to, for example, a positioner or
electro-pneumatic converter having a large input inductance component.
Make sure the input inductance component of the equipment to be
connected is no greater than 100 µH.
• If the equipment's input inductance component is unknown,
connect the instrument to the equipment as shown in the figure below,
and measure the generated current at the MEASURE side.
If the reading does not stabilize or an accuracy error results at that point,
the input inductance component is likely to be greater than 100 µH.
CA150
H L mA
H L
MEASURE
SOURCE
H
L
Equipment such
as a converter
DCA
DCA
• If the equipment's input inductance component is too large,
connect a 200 Ω resistor R and a 1 µF capacitor C to the instrument's
outputs, as shown in the figure below.
This setup makes it possible to connect an input having an inductance
component of up to 3 H to the instrument.
Note, however, that the instrument's response time becomes 1 second
(at load resistances no greater than 2 kΩ).
Do not use this circuitry for purposes other than current generation (DCA),
otherwise errors may be produced.
CA150
H L
SOURCE
H
L
Equipment such
as a converter
DCA
99020
R
C
R: 200
Ω
±10%, 1/4 W
C: 1µF ±10%, 50V
This combination of a resistor (200 Ω) and capacitor (1 µF) is
available as an accessory (Model: 99020).
4.3 Source DC Current (DCA) Signals
