Flowmeters and System Solutions

Flowmeters and System solution.





The ROU28S is a receiver designed for MASFLO-OVAL Ⅱ (thermal mass flowmeter/controller).
Functions necessary for flow measurement/control are integrated into specialized units.
The ROU28S enables the simple and cost-effective configuration of flow measurement/control systems.

Product Specifications


●Small and lightweight receiver equipped with basic functions necessary for flow measurement/control.
●Flow rate value, accumulated flowrate value and flowrate set-point can be switched to the display.
●A flow rate adjustment device and an external input switch are placed on the front, realizing an easy-to-use layout.
●As standard specifications, it includes external output (analog and pulse) and external control input functions.
Therefore, flexibility of system design can be improved.
●By combining the readout unit with the MASFLO-OVAL II series, a flow measurement system can be easily configured.


Item Description
Measurement Measurement types Instantaneous flowrate value/accumulated flowrate value
Measurement method A/D conversion method
Resolution: Approximately 1/7000 (relative to full-scale input)
Input measurement interval: Approximately 20 ms
Low-cut 0 to 29% of maximum analog input (can be set arbitrarily)
Display Display Red LED, Character Height: 8 mm (Zero-Blanking Method)
Display switching Switch between displaying flowrate value and accumulated value using the ▲ key
(Requires setting in “Mode No.4”) ※When the DISP switch is set to OUT
RA lamp Lights up (red) during flowrate value display
TO lamp Lights up (red) during accumulated value display
OV lamp Lights up (red) when the displayed measurement value exceeds the range
(During right-shifted display, it blinks)
OUT1 lamp Lights up during output of Alarm output OUT1
OUT2 lamp Lights up during output of Alarm output OUT2
Instantaneous value
Measuring accuracy ±0.3% (F.S.) ±1 digit (at 23°C) for analog input
Scaling method Arbitrary setting of instantaneous flowrate value display at maximum analog input
(0.001 to 9999)
Display range 0 to 9999 (When the displayed value exceeds this range, “9999” blinks and OV Lamp lights up)
Decimal point representation Set at the maximum display value (Mode No.1).
Display sampling time Averaging the display in approximately 0.5 seconds (fixed)
Least significant digit
Averaging the display in approximately 0.5 seconds (fixed)

Least Significant Digit Correction: Selectable from “Normal,” “0 fixed,” and “0 or 5”

Accumulated value
Measuring accuracy ±0.3% (F.S.) ±1 digit (at 23°C) for analog input
Scaling method Arbitrary setting of accumulated value per hour at the maximum analog input value by mode setting
Display range 0 to 99999
Decimal point display Selectable from 1 to 4 decimal places.
Over (OV) display When the displayed value exceeds 99999, it automatically shifts one digit to the right (continuing with right-shifted display).
During right-shifted display, the OV Lamp blinks. If the display exceeds the x10 scale, the OV Lamp lights up and
the display becomes endless.
Display offset The accumulated value after reset can be arbitrarily set in the range of 0 to 99999 by setting the display offset value.
Input signal Flowrate signal DC 0 to 5V, D-sub, input resistance 330KΩ
External setting signal DC 0 to 5V, terminal block, input resistance 330 KΩ
Operating section Mechanical dial
Minimum scale of 10 rotary type potentiometer: 1/50 turns
Equipped with a lock lever (to fix rotation and scale)
(The scale on the dial serves as a reference for the amount of rotation)
Set it to the desired flowrate for control
VOR switch Not used for MASFLO-OVAL II (CONT only)
Command changeover switch
EXT: The external setting value signal becomes the display for the flowrate setpoint.
INT: The CMDSET mechanical dial (CMD) setting becomes the flowrate set-point display.
Display changeover switch
SET: Displays the flowrate set-point (relative to COMMAND).
OUT: Displays the instantaneous and accumulated flowrate values.
Operation setting switch Key switches of MODE, ▲, and RST
Output-related Power supply rating ±15VDC, 250mA each
or DC +15V 150mA and DC -15V 350mA also supported
Ripple noise: 30mV or less
Setting signal output DC 0 to 5V, 5mA, D-sub
External signal output DC 0 to 5V, terminal block
Valve opening/closing output Not used for MASFLO-OVAL II
Alarm and synchronous
Output terminal Output from terminal blocks 11-12 (OUT1) and 13-12 (OUT2) (common to COM)
Comparison method Selectable from upper and lower limits
Output mode Comparison/synchronization pulse (OUT1: Selectable via mode)
Preset value setting Can be set arbitrarily in the preset value setting mode.
Alarm, synchronous
output, and others
Output judgment Output determined by comparing the displayed value with the preset value
Output method NPN open collector output, 2 points

Maximum rating: DC30V, 50mA, MAX

Data backup Writes the setting values for each mode and accumulated measurement to FRAM (Rewriting limit: 100,000 times or less,

approximately 10 years of retention)

Mode protect function Switching selection based on mode protect setting

When “ON,” the set value cannot be changed; when “OFF,” the set value can be changed

Warm-up time 30 minutes or more after power-on
Power supply AC 100 to 240V (-15% / +10%), 270 mA max

50/60Hz, approx. 35VA or less

Others Operating temperature and
humidity ranges
0 to 50°C, 30 to 80%RH (without condensation)
Weight and outside dimensions Approximately 400g, W96 × H48 × D156 mm
Main body color Black
Housing material ABS
Operating environment Indoor use, Maximum altitude: 2,000m, Overvoltage category II, Pollution level 2
Low voltage directive EN61010-1
EMC EN61326-1
EN55011(Group1 ClassA)、EN61000-4-2、EN61000-4-3、


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Product Specifications