Hioki DM7275 Series - Appendix; Appx. 1 Block Diagram

Appx.1
Appendix
Appx.1 BlockDiagram
CPU
GP-IB/
RS232C
EXT I/O
Switching
power
supply
USB
Contact
check
Low
High
A
B
Measurement block Control block
C
D
E
F
V
QTM
G
LAN
A/D
Meas-circuit
power
supply
• The voltage detected between the HIGH and LOW terminals is adjusted appropriately and
connected to a high-impedance amp. (A)
From the 100 mV range to the 10 V range, the input resistance is switched between high-Z (10
G
Ω
or greater) and 10 M
Ω
. For the 100 V range and 1000 V range, the input resistance is xed
to 10 M
Ω
.
• The detected voltage adjusted in (A) is converted into a digital value by a high-stability reference
voltage source and a high-resolution A/D converter. (B)
• The impedance between HIGH and LOW is measured by the contact check circuit. If the
impedance is high, a contact error is determined to have occurred. The contact check function
can be used from the 100 mV range to the 10 V range. (C)
• The instrument has a built-in temperature measurement circuit, making it possible to correct
voltage measured values according to the temperature when measuring a target that exhibits a
high degree of temperature dependence. (D)
• A high-speed CPU makes possible high-speed measurement and a speedy system response. (E)
• The measurement block is isolated from the control block, increasing the circuit’s resistance to
the effects of noise. (F)
• Use of a switching power supply with a wide input range from 100 V to 240 V enables stable
measurement, even in environments in which stable power cannot be supplied. (G)
Appendix
10
9
8
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6
5
4
3
2
1
Appx.
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