NF FRA5022, Инструкция по эксплуатации

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4.5 Servo System Measurement
FRA5022
4-9
4.5 Servo System Measurement
It is possible to obtain the servo system loop gain A
β
by inserting
FRA5022
oscillator into
a control loop and to measure the signal ’ s V
1
and V
2
before and after.
Figure 4-7 Connection for servo system measurement
⚫
When the control loop is cut, a significant output is generated. The system under
test may be damaged and users can be put at risks. Use a signal injection
resistor to ensure that even if the connection to
FRA5022
’ s oscillator is cut the
control loop is not opened. Firmly fix the resistor to prevent it from coming away.
⚫
When the input signal level (AC amplitude, etc.) is too strong, a significant
output is generated. The system under test may be damaged and users can be
put at risks. Use a small signal level first and slowly increase it to ensure you
work in safe conditions.
⚫
The connection between
FRA5022
and the system under test may generate
unexpected behavior like an oscillation. There is a few 100pF floating
capacitance (capacitance vs the case) for the analyzer
’ s input or the oscillator ’ s
output, together with the connection cable stray capacitance, it is possible to put
the system under test into an unstable state.
FRA5022
’ s maximum output current is
±
100mA.
If the influence on the system under test response is not too important, set the
resistor for the input signal inserted to the circuit to at least 50
Ω
. During the
measurement, this resistor value in parallel with the oscillator ’ s output resistance
of 50
Ω
will be inserted into the control loop. If a lower resistor value is inserted,
modify AC amplitude and DC bias so that the current does not exceed the
maximum output current. A combined peak value not exceeding
±
5V is safe.
！
WARNING
！
CAUTION
β
A
V
1
V
2
CH1 CH2 OSC
FRA
SUT : System Under Test
MEAS mode = CH2/CH1
A
β
= V
2
/ V
1
Resistor
Signal injection resistor
（
OSC
：
OSCILLATOR
）