3-4
IM 701450-51E
3.3
Connecting the Probe
Input Terminals
Connect the probe (or other input cables such as the BNC cable) to any of the input
terminals (4 terminals marked as CH1 to CH4 on the DL7440 and 8 terminals marked
CH1 to CH8 on the DL7480) located on the lower section of the front panel. The input
impedance is 1 M
Ω
±
1.0% and approximately 20 pF or 50
Ω
±
1.0%.
CAUTION
• The maximum input voltage for 1-M
Ω
input is 400 V (DC + ACpeak) or 282
Vrms when the frequency is 1 kHz or less. Applying a voltage exceeding either
of these voltages can damage the input section. If the frequency is above 1
kHz, the input section may be damaged even when the voltage is below the
values specified above.
• The maximum input voltage for 50-
Ω
input is 5 Vrms or 10 Vpeak. Applying a
voltage exceeding either of these voltages can damage the input section.
DL7440
1M
Ω
/20pF 400Vpk CAT II 50
Ω
5Vrms, 10Vpk
CH
1
CH
2
CH
3
CH
4
DL7480
CH
7
1M
Ω
/20pF 400Vpk CAT II 50
Ω
5Vrms, 10Vpk
CH
1
CH
2
CH
3
CH
4
CH
5
CH
6
CH
8
Precautions to Be Taken When Connecting a Probe
• When activating triggers on the SPI Bus signal, connect the signals to the input
terminals as follows:
CH1:
Clock signal (SCK)
CH2:
Master output slave input signal (MOSI)*
CH3:
Master input slave output signal (MISO)*
CH4:
Slave select signal (SS)*
*
•
When performing analysis, CH2 and CH3 can be connected to MOSI or MISO.
•
During the analysis, the DL7440/DL7480 handles the data of the signal connected to CH2
and CH3 as Data1 and Data2, respectively. The slave select signal is displayed as CS on
the analysis condition setup menu and can be applied to any channel between CH4 and
CH8 or any Pod A bit (A0 to A7) of the logic input (optional).
•
To activate triggers on the SPI Bus signal, be sure to apply the slave select signal (SS) to
CH4.
• When connecting a probe to the instrument for the first time, perform phase correction
of the probe as described in section 3.5, “Compensating the Probe (Phase
Correction)” in the
DL7440/DL7480 User’s Manual (IM701450-01E). Failure to do so
may result in unstable gain across different frequencies, thereby preventing correct
measurement. Calibration must be performed for each channel that is to be
connected.
• Note that if the object being measured is directly connected to the instrument without
using a probe, correct measurements may not be possible due to the loading effect.