3.4 I/O Connection
CA5350
3-12
3.4.2 Connection with lock-in amplifier, etc
When connecting the output (
INVERTING OUTPUT
) of
CA5350
to measurement
equipment like a lock-in amplifier or a digitizer, it is necessary to pay attention to noise
current due to ground loop.
Because I/O of
CA5350
is insulated from the enclosure, it is difficult to be affected by
ground loop. However, it is necessary to pay careful attention to the grounding of
equipments connected to the output of sensor or
CA5350
.
(1) When the single source is grounded
When the signal source is grounded, do not ground the input of measurement
equipments (lock-in amplifier, etc.) those connected to the output of
CA5350
. Ground
loop will be formed and noise current will flow, because of which the common mode noise
may easily occur.
信号源
CA5350
↑
同軸ケーブル
同軸ケーブル
CURRENT
INPUT
INVERTING
OUTPUT
計測器
(ロックインアンプ 等)
INPUT
接地
接地しない
(差動入力 等)
Figure 3-11 When the signal source is grounded
(2) When the signal source cannot be grounded
When the signal source cannot be grounded, as shown in
“Figure 3-12 When the signal
source
cannot be grounded”
, ground the shielded side of coaxial cable to the input of
measurement equipment. If use the measurement equipment without grounding, high
voltage will occur because of electrical charges accumulated in the shield of coaxial cable,
which may cause electric shock or damage the machine. Besides, electrostatic induction
may easily mix noise in the signal.
信号源
CA5350
↑
同軸ケーブル
同軸ケーブル
CURRENT
INPUT
INVERTING
OUTPUT
計測器
(ロックインアンプ 等)
INPUT
接地する
Figure 3-12 When the signal source cannot be grounded
Coaxial cable
Coaxial cable
Signal source
Measurement device
(Lock-in amplifier, etc.)
Grounding
Coaxial cable
Coaxial cable
Source of signal
Grounding
Measurement device
(Lock-in amplifier, etc.)
Do Not ground
(Differential input, etc.)
