Nohken VQ20-R00 User manual

ＴＳ０２－１０００１５
ＩＮＳＴＲＵＣＴＩＯＮ ＭＡＮＵＡＬ
FOR
TUNING FORK LEVEL SENSOR
MODEL: ＶＱ２０
Revision 2020-01-08

- ADD 1 -
Read this manual carefully for safe usage.
・This manual applies to general purpose equipment. For equipment intended for
use in potentially explosive atmospheres, see applicable manuals.
・This manual contains important information on handling, inspection and
operation of the equipment indicated on the cover page. Before handling the
equipment, read this manual carefully.
・Instructions in documents submitted by Nohken or its representative have
higher priority than those in this manual.
・Keep this manual within easy access.
・Depending on environment, the equipment may not satisfy specifications
shown in this manual. Check the application conditions carefully beforehand.
・Please contact our sales office for any questions or comments about the
equipment or this manual. Sales offices are shown on the back of the manual.
Safety Symbols:
WARNING Means a potentially hazardous situation which,
if necessary precautions are not observed, can result
in death, serious injury and/or considerable material
damage.
CAUTION Means a hazardous situation which, if necessary
precautions are not observed, can result in minor or
moderate injury or damage to the device.
Means prohibited actions.
Means mandatory actions.

- ADD 2 -
WARNING
This equipment is NOT intended for use in potentially hazardous
atmospheres. Never use it where flammable gas or vapor may be
present. Failure to observe this may result in ignition of flammable
gas or vapor, causing disaster.
Do not alter or disassemble the equipment, unless you have been
instructed to do so by Nohken or its representative.
Failure to observe this may result in:
- malfunction of or damage to the equipment or connected devices;
- ignition;
- electric shock or user injury.
Turn off the equipment before wiring or inspection. Otherwise
leakage or short circuit may cause ignition or electric shock.
After wiring is complete, always check for its correctness. Wrong
wiring may cause:
- damage to or malfunction of the equipment or connected devices;
- ignition;
- electric shock or user injury.
Turn off the equipment immediately in case smoke, unusual smells
or sounds are noticed. Do not supply power until problems are
solved.
CAUTION
Handle the equipment with care. Do not drop, throw, or give
a strong shock to avoid damage.
Observe operation conditions specified in the manual. Use outside
the specified conditions may result in malfunction of or damage to
the equipment or connected devices, ignition, user injury, or
electric shock.
Perform operation tests before actual application to ensure
performance. Install back-up instruments based on different
technologies if failure of this equipment is expected to result in
a serious incident.

- ADD 3 -
CAUTION
Check carefully for chemical compatibility of materials of
construction before installation.
Use the flange, thread or somewhere close to the process
connection to handle the equipment. Do not use the terminal box
(housing) to avoid dropping the equipment, and resultant damage
to the equipment or user injury.
Equipment 50cm or longer:
Lay the equipment when not in use. Otherwise it may fall and
damage itself or things around it, and cause user injury.
Always connect the protective terminal inside the housing
to the ground. (Grounding resistance: 100Ωmax.)
Otherwise leak may occur to cause electric shock
when error occurs.
When connecting to inductive or lamp loads:
Ensure the maximum voltage/current ratings will not be exceeded
to avoid damage to the relay contacts.
Use lightening arrestors or surge absorbers to prevent:
- malfunction, damage, or ignition of the equipment and connected
instruments;
- electric shock or injury.

- ADD 4 -
INTRODUCTION
A) This manual applies to standard models. Please note that information in
this manual may not be applied to customized versions.
B) We are willing to help customers select a suitable model or provide
information about chemical compatibility of materials used, but the
customer is responsible for the decisions made.
C) We always welcome suggestions and comments about this manual.
Please contact our sales office when you have questions or comments.
D) Component replacement:
The equipment design is regularly reviewed and improved. The same
components therefore may not be available when replacement is required.
In such cases, different components or products may be supplied. Please
contact our sales office for detail.
E) The contents of this manual are subject to change without prior notice as
a result of improvement of the equipment.
WARRANTY & DISCLAIMER
A) Nohken warrants the equipment against defect in design or material, and
workmanship for a period of one (1) year from the date of original
shipment from Nohken’s factory.
B) Nohken will not assume liability for loss nor damage resulting from the
use of the equipment.
C) Nohken will not assume liability for damage resulting from:
C-a) not observing instructions in this manual;
C-b) installation, wiring, operation, maintenance, inspection, or storing in
a manner not outlined in this manual;
C-c) unauthorized alterations and repairs;
C-d) the use of or replacement with components not provided by Nohken;
C-e) devices or instrument other than those manufactured by Nohken;
C-f) the use not described in Chapter 1 Purpose of Use of the manual;
C-g) force majeure including, but not limited to, fire, earthquake, tsunami,
lightning strike, riot, commotion, war, armed conflict or terrorist
attack, radioactive pollution, act of God, governmental decisions or
actions, and compliance with laws and regulations.
THE PROVISIONS OF THIS SECTION DO NO LIMIT YOUR LEGAL RIGHTS.

Table of Contents
1.PURPOSE OF USE …………………………………………… 1
2.DESCRIPTION …………………………………………… 1
2.1 Product Overview …………………………………………… 1
2.2 Principle of Operation …………………………………………… 1
3.SPECIFICATIONS …………………………………………… 1
3.1 Model Numbering …………………………………………… 1
3.2 Specifications …………………………………………… 2
3.2.1 Common …………………………………………… 2
3.2.2 Model specific …………………………………………… 3
3.3 Outline Drawing …………………………………………… 5
4.HANDLING NOTES …………………………………………… 6
5.INSTALLATION …………………………………………… 7
5.1 Unpacking …………………………………………… 7
5.2 Switching Point …………………………………………… 7
5.3 Mounting …………………………………………… 8
5.3.1 Threaded version …………………………………………… 8
5.3.2 Flanged version …………………………………………… 8
5.3.3 Sanitary version …………………………………………… 8
5.4 Handling Notes …………………………………………… 9
6.WIRING …………………………………………… 13
6.1 Wiring …………………………………………… 14
6.1.1 Cable …………………………………………… 14
6.1.2 Parts name …………………………………………… 14
6.1.3 Wiring …………………………………………… 15
6.2 Cable Inlet …………………………………………… 18
6.3 Placing the Cover …………………………………………… 19
7.ADJUSTMENT …………………………………………… 20
8.MAINTENANCE AND INSPECTION
………………………… 22
9.STORING …………………………………………… 22
9.1 Conditions …………………………………………… 22
9.2 Precautions …………………………………………… 22
10.TROUBLESHOOTING …………………………………………… 23
11.GLOSSARY …………………………………………… 24

- 1 -
1. PURPOSE OF USE
Tuning Fork Level Sensor VQ is designed to measure material level in a tank or piping. Do not use
it for any other purpose.
2. DESCRIPTION
2.1 Product Overview
VQ is a compact level sensor ideal for integration into machinery. Wetted parts, the fork* and process
connection, are in 316L stainless steel to offer high corrosion resistance. The cover has a window,
so the user can check operation status by LED without opening the cover.
2.2 Principle of Operation
The fork assembly incorporates a piezo-electric crystal*. This crystal oscillates the detecting
element, the fork, at a frequency. The frequency changes when the fork is covered with the material.
The electronics of the sensor detects this change in frequency, and gives an output to report
presence or absence of the material.
3. SPECIFICATIONS
3.1 Model Numbering
VQ20-□ □ □ □
Code Surface finish
(blank) Without coating
E ECTFE coating (flanged version only)
B #400 buffing (sanitary version only)
Code Insertion length
0
Standard R threaded : 51mm
Flanged : 65mm
Sanitary : 72mm
X
Extended R threaded : 100 to 3000mm
Flanged : 95 to 3000mm
Sanitary : 95 to 3000mm
Coated : 95 to 440mm
Code Output
0 2 wire
1 3 wire (NPN/PNP open collector)
2 Dry contact relay* (SPDT)*
Code Process connection
R R thread
F Flange*
S Sanitary connection*
Z Other connections
General purpose
* See 11. GLOSSARY.

- 2 -
3.2 Specifications
3.2.1 Common
Name Tuning Fork Level Sensor
Model VQ20
-R□0
VQ20
-R□X
VQ20
-F□0
VQ20
-F□X
VQ20
-F□0E
VQ20
-F□XE
VQ20
-S□0B
VQ20
-S□XB
Measured material Liquids
Operation
Specific gravity 0.6 to 2.0
Viscosity 0.2 mPa・s to 10 Pa・s
Switching point (water)
(section 5.2)
approx. 13.5 mm from tip (vertical)
approx. 3 mm above the center line (horizontal)
Hysteresis (water) approx. 2 mm
Mechanical characteristics
Withstand pressure
(static) 6 MPa Max. (excluding process connection)
Vibration resistance
(JIS C 60068-2-6)
10 to 58.1 Hz – half amplitude 0.15 mm
58.1 to 150 Hz – 20 m/s2 acceleration
10 to 150 Hz – 20 sweeps
Environmental
Working temperature
Wetted parts -40 to +150 ℃
Housing -40 to +80 ℃ (no dew condensation),
degraded to +50 ℃ at and below process
temperatures +60 ℃.
Humidity 85 %RH Max.
Protection class
Wetted parts IP68 (10 MPa static for 15 minutes)
Housing IP65/67
Material
Wetted parts
316L stainless steel,
nickel based alloy (BNi-2)
316L stainless
steel, nickel
based alloy
(BNi-2),
ECTFE (coating,
black, 0.1 to
0.4mm thick)
316L stainless
steel,
nickel based
alloy (BNi-2)
Housing Glass reinforced PBT (with anti-static agent),
PC (window for LED)
Process connection Threaded, R1 Flanged,
JIS 5K 50A
Flanged,
JIS 5K 50A RF
Sanitary
ISO 2S or
equivalent
Wetted parts maximum
(Section 3.3, Fig. 3) 26 mm 28 mm 28.8 mm 28 mm
Cable inlet G 1/2 or equivalent, 11 mm deep
Approx. mass
(insertion length in mm) 0.5 kg 2.2 kg (1000) 1.9 kg 3.6 kg (1000) 1.9 kg 2.6 kg (440) 0.7 kg 2.5 kg (1000)
Housing rotation 330°

- 3 -
3.2.2 Model specific
(1) 2 wire
Model VQ20
-R00
VQ20
-R0X
VQ20
-F00
VQ20
-F0X
VQ20
-F00E
VQ20
-F0XE
VQ20
-S00B
VQ20
-S0XB
Operating characteristics
LED (red) operation ON - Lights continuously
OFF - 1 flash per 3 seconds
delay - 7 flashes per second
overload - 3 flashes per second twice, and then goes out for 1 second
error - 3 flashes per second for 5 times, and then goes out for 1 second
Electric characteristics
Power supply 24 to 240 V AC ±10 %, 50/60 Hz
24 to 54 V DC ±10 %
Power consumption approx. 0.5 VA at 100 V AC with output OFF
approx. 1.0 VA at 200 V AC with output OFF
approx. 0.1 W at 24 V DC with output OFF
Relay output 2 wire
- wet=ON/dry=ON selectable
- ON/OFF delay timer selectable
Delay timer Wet = ON Dry = ON
ON delay approx. 0.5 to 30 sec. approx. 0.3 sec.
OFF delay approx. 0.3 sec. approx. 0.5 to 30 sec.
Output rating Load current: 12 to 500 mA AC/DC
Remaining voltage: 12 V AC/DC Max. with output ON
Insulation resistance 100 MΩ Min. at 500 V DC, between power and E terminals
Withstand voltage 2200 V AC for 5 seconds, between power and E terminals
(2) 3 wire
Model VQ20
-R10
VQ20
-R1X
VQ20
-F10
VQ20
-F1X
VQ20
-F10E
VQ20
-F1XE
VQ20
-S10B
VQ20
-S1XB
Operating characteristics
LED (red) operation control output ON - Lights continuously
control output OFF - 1 flash per 3 seconds
delay - 7 flashes per second
error - 3 flashes per second for 5 times, and then
goes out for 1 second
Electric characteristics
Power supply 24 V DC ±10 %
Power consumption approx. 0.1 W
Relay output 3 wire
- NPN open collector (OUTPUT 1)
- PNP open collector (OUTPUT 2)
- Wet=ON/dry=ON selectable
- ON/OFF delay timer selectable
Delay timer Wet = ON Dry = ON
ON delay approx. 0.5 to 30 sec. approx. 0.3 sec.
OFF delay approx. 0.3 sec. approx. 0.5 to 30 sec.
Output rating Load current : 100 mA DC Max.
Load voltage : 26 V DC Max. (OUTPUT 1)
Remaining voltage : 1 V DC Max. with OUTPUT 1 closed
2 V DC Max. with OUTPUT 2 closed
Insulation resistance 100 MΩ Min. at 500 V DC, between power/output and E terminals
Withstand voltage 2200 V AC for 5 seconds, between power/output and E terminals

- 4 -
(3) Relay
Model VQ20
-R20
VQ20
-R2X
VQ20
-F20
VQ20
-F2X
VQ20
-F20E
VQ20
-F2XE
VQ20
-S20B
VQ20
-S2XB
Operating characteristics
LED (red) operation relay energized - Lights continuously
relay de-energized - 1 flash per 3 seconds
delay - 7 flashes per second
error - 3 flashes per second for 5 times, and then goes
out for 1 second
Electric characteristics
Power supply 100 to 240 V AC ±1 0%, 50/60 Hz
24 to 54 V DC ±10 %
Power consumption approx. 0.5 VA at 100 V AC
approx. 1.0 VA at 200 V AC
approx. 0.1 W at 24 V DC
Relay output Dry contact relay (SPDT)
- wet=ON/dry=ON selectable
- ON/OFF delay timer selectable
Delay timer Wet = on Dry = on
ON delay approx. 0.5 to 30 sec. approx. 0.3 sec.
OFF delay approx. 0.3 sec. approx. 0.5 to 30 sec.
Output rating Maximum : 250 V, 3 A AC (resistive)
30 V, 3 A DC (resistive)
Minimum : 5 V 10 mA DC (resistive)
Insulation resistance 100 MΩ Min. at 500 V DC, between power/relay and E terminals
Withstand voltage 2200 V AC for 5 seconds, between power/relay and E terminals

- 5 -
3.3 Outline Drawing
① Window for LED – to check operation status by LED
② Cover
③ Cable inlet (G1/2, 11mm deep)
④ External earth terminal (M4)
⑤ Housing
⑥ Threaded connection
⑦ Fork – detects material presence/absence
⑧ Flange
⑨ Sanitary connection
VQ20-R□0
VQ20-F□0 VQ20-F□0E VQ20-S□0B
Fig. 3

- 6 -
4. HANDLING NOTES
Observe instructions below when handling the sensor, or faulty operation or user injury may result.
(1) Lay the sensor on a flat surface. Do not stand it
to prevent it from falling.
Support the sensor with wood piece to avoid rolling,
or bent or damaged fork.
Always ensure the fork will not be damaged.
(2) Avoid corrosive atmosphere (NH3, SO2, Cl2). Such
atmosphere may penetrate the housing and damage
internal components.
(3) Avoid or protect against vibration.
(4) Wear gloves when the process temperature is +45℃
or higher, or +5℃ or lower to avoid injury.
(5) Do not give a shock to the fork to avoid damage.
(6) Do not over-rotate the housing. It can be rotated
for up to 330˚.

- 7 -
5. INSTALLATION
WARNING
This sensor is not intended for use in hazardous areas*. Never use it in areas where
flammable or explosive gases or vapors may be present.
5.1 Unpacking
(1) Open the packaging and take out the sensor. Check against nameplate that the sensor is what
you have ordered. If not, please contact our sales office.
(2) Check the sensor for visible damage. If any, please keep the packaging and contact our sales
office.
(3) Do not drop, throw, crush or give a strong shock to the sensor. Be especially careful not to
damage the fork.
CAUTION
Do not drop, throw, crush, or give a strong shock to the sensor
when unpacking.
Do not hold the sensor by the fork. Hold it by the body.
(Fig. 5-1)
Fig. 5-1
5.2 Switching Point
(1) Vertically mounted, with water - approximately 13.5mm from the fork tip
(2) Horizontally mounted, with water – approximately 3mm above the center
Fig. 5-2
* See
11. GLOSSARY .

- 8 -
5.3 Mounting
Align the fork gap with the flow direction. Use the markings when orienting the sensor.
5.3.1 Threaded version
Use a tool to mount the sensor.
Hexagon on the thread is of 41mm A/F.
Fig. 5-3
5.3.2 Flanged version
Place the sensor flange on the tank flange, and secure them using
a suitable tool and bolts according to the applicable standards.
Use a gasket suitable for working conditions to prevent leak.
Note that bolts and gaskets are optional.
Fig. 5-4
5.3.3 Sanitary version
Use a clamp to mount this version.
Select a gasket suitable for the measured material.
Fig. 5-5

- 9 -
5.4 Handling Notes
CAUTION
Never alter the sensor in any way to avoid faulty operation
or damage. (Fig. 5-6)
Do not give a shock to the sensor to avoid faulty operation
or damage.
Ensure the fork protrudes into the tank or piping. Otherwise
faulty operation may result due to for example the sensor
erroneously reading buildup. (Fig. 5-7)
Ensure no material buildup on the fork. Clean periodically
to avoid faulty operation. (Fig. 5-8)
Use a tool on the hexagon of the sensor when mounting threaded
Version. Never hold the sensor by the housing or pipe. (Fig. 5-9)
Avoid proximity to inlet/outlet, agitator, or other high flow
or bubble sources. Otherwise instable or faulty operation may
result.(Fig. 5-10)
Fig. 5-7 Fig. 5-9
Fig. 5-6 Fig. 5-8 Fig. 5-10

- 10 -
(1) For horizontal mounting, orient the sensor as shown. Make sure the marking on the hexagon faces
upwards or downwards.
Fig. 5-11
CAUTION
Incorrectly mounted sensor causes sticky material to remain on
the fork. This may cause faulty operation.
(2) On piping, mount the sensor as shown in Fig. 5-12. Incorrectly mounted sensor
may cause cavitation between the tines (Fig. 5-13) and thus faulty operation.
Fig. 5-12
Fig. 5-13
(3) Avoid bubbles. The sensor may erroneously detect them.

- 11 -
(4) Fig. 5-14 shows mounting examples.
Fig. 5-14
CAUTION
Allow clearance of at least 13mm between the fork tip and
the tank/pipe wall. Otherwise faulty operation may result
under high flow conditions.
(5) In sticky material applications, response to wet-to-dry may be slower.
Response to dry-to-wet will not be affected.
(6) Remove material buildup periodically.

- 12 -
(7) Ensure that the fork protrudes into the tank or piping. Otherwise faulty operation or slower
response may result with sticky material, causing the pump to run dry. (Fig. 5-15)
The fork must protrude for at least 27mm in any cases including small piping, and 13mm of
clearance between the fork tip and the piping wall must be ensured. (Fig. 5-16)
The sensor can be mounted on piping with inner diameter 40mm or larger. 57mm or larger piping
is recommended.
Fig. 5-15 Fig. 5-16
(8) Housing can be rotated for approximately 330˚. Take measures to prevent water or moisture
penetration. (Fig. 5-17, 5-18)
Fig. 5-17
Fig. 5-18

- 13 -
6. WIRING
CAUTION
Hold the sensor by the housing when rotating the cover.
Holding other components may damage the pin to limit
the rotation of the housing.
Use cabling whose conductor area 2.5mm2 or smaller.
Use a surge absorber* on devices that can generate surges in the
vicinity of the sensor.
Always connect the internal earth terminal to the ground.
(Grounding resistance: 100Ω Max.)
Connect if necessary the external earth terminal on the housing
to the ground as well. (Grounding resistance: 100Ω Max.)
Do not exceed ratings for connected load to avoid damage to the sensor.
Add a suitable relay to switch loads exceeding these ratings.
Ratings:
- 2 wire (VQ20-□0□): 500mA AC/DC
- 3 wire (VQ20-□1□): 100mA DC
- Relay (VQ20-□2□): 250V, 3A AC (resistive), 30V, 3A DC (resistive)
Run the sensor cabling as far from power lines as possible to
avoid induction. Use a metal conduit if necessary.
Avoid proximity to sources of strong magnetic fields such as motors and
solenoid valves, or devices creating high frequency magnetic field such
as ultrasonic cleaners and transceivers.
* See 11. GLOSSARY .
WARNING
Disconnect power before wiring, or electric shock may result. Ignition
or short circuit may also result due to leakage or charged components
contacting each other.
Do not startup sensors with fault in protective functions such as
protective earth or fuse.
Ensure correct voltage to avoid damage to the sensor or human injury.

- 14 -
6.1 Wiring
6.1.1 Cable
Strip the cable tip for 6mm. The sensor accepts conductor size of up to 2.5mm2.
Use cable with 0.75mm2 conductor to jumper terminals.
Terminal screws have a combination head. Use a slotted screwdriver of 0.6 x 3.5mm,
or another suitable screwdriver.
If cable lugs are used, select ferrule terminals (insulated bar type cable lug)
with 6mm insulation.
6.1.2 Parts name
① Terminal block – for power line and relay wiring
② Fail-safe switch (FS) – switches operation modes
③ Delay switch (DELAY) – switches ON, OFF delay timers
④ Test button (TEST) – switches operation modes for testing
⑤ Delay trimmer (DELAY TIME) – fine tunes delay time
⑥ Status LED
- 2 wire (VQ20-□0□)
Lights continuously when the output is ON and flashes when the output is OFF.
- 3 wire (VQ20-□1□)
Lights continuously when the control output is ON, and flashes when the control
output is OFF.
- Relay (VQ20-□2□)
Lights continuously when relay is energized, and flashes when relay is de-energized.
⑦ Protective earth – to be connected to the ground. (grounding resistance: 100Ω Max.)
VQ20-□0□ VQ20-□1□ VQ20-□2□
Fig.6-1: internal layout