12
IM 767361-01E
Name and Functions of Each Part
System Block Diagram
The fluid pressure to be measured is sent to the resonant sensor section.
The resonant sensor section consists of a resonant sensor (developed by
YOKOGAWA) and an excitation circuit to convert the fluid pressure to a
frequency signal. The frequency signal is then sampled in the pressure sensor
section at the rate corresponding to the current measurement mode and
converted into a pressure value. As necessary, the converted pressure value
undergoes processing such as averaging, and is then sent to the main CPU and
displayed.
The /DA option section is made up of a D/A output section with comparator
output as well as an I/O section that controls the external trigger input. The D/
A output section outputs the D/A signal corresponding to the pressure value
received from the pressure calculation section at 2 ms period. The comparator
output section outputs the results obtained by comparing the upper and lower
limits of pressure to the measured pressure (synchronized to D/A output). When
put on HOLD, measurement is performed one time when a falling signal is input
to the external input trigger.
There are three measurement modes (normal, medium-speed, high-speeed)
on the MF210F. In addition, dynamic mode is availalble when the /DA option is
installed. This mode provides high precision pressure measurements and high-
speed D/A output at the same time.
The MT220 has a DMM function and a 24 VDC output function.
The DMM is controlled by the main CPU. The input current and voltage signals
are converted to digital signals by the A/D converter and sent to the main
CPU. In the main CPU they are converted to current and voltage values, then
averaging is performed (in the same manner as occurs with pressure values)
and the results are displayed. 24 VDC output is turned ON and OFF by the
main CPU. The instrument has an excess current detection function, and
detection signals are sent to the main CPU.
DMM section
Pressure Measurement Section
Pressure
calculation
section
Main CPU
Display and operating keys
Power supply
Communications interface
(GP-IB or RS-232)
D/A output section
/DA Option
D/A output
Comparator output
External trigger input
100 to 120 VAC
200 to 240 VAC
12 VDC
Battery backup
I/O input output
section
Silicon
resonant sensor
section
V
COM
A
Input
section
24 VDC output section
24V
COM
MT220 Only
A/D
converter
Control
section
Output
section
Control
section
