Nagano Keiki GC31 User manual

TY-GC31-004A
Rev.B
GC31 Digital Pressure Gauge
Instruction Manual
NAGANO KEIKI CO., LTD.
Oct., 2023
8.0

TY-GC31-004A 1/24
Rev.B
For proper and safe operation
GC31 Digital Pressure Gauge is a compact digital pressure gauge which complies with the
EMC directive.
In order to safely and properly utilize this device, please read this instruction manual carefully.
Incorrect operation may cause malfunction, damage, or an accident.
Indicates that incorrect use may result in severe injury or loss of life.
Indicates that incorrect use may result in risk of injury or property damage.
1. Do not apply pressure greater than the maximum allowable pressure. This
may cause damage or burst of the pressure element and also injury or
damage to the surroundings.
2. Use of a non designated power source may cause a fire or electrical shock.
3. Do not apply excessive weight, vibration or shock. This may cause damage
or burst of the unit and release of the measurement gas. It will result in injury
or damage to the surroundings.
4. This device is not explosion -proof. Do not use this device in the areas
where flammable or explosive gases or liquids are located.
5. Perform wiring according to the wiring faceplate or the wiring instructions of
this instruction manual. Incorrect wiring may cause injury or a fire.
6. Use this device within the operating temperature range. Using outside the
range of operating temperature may cause malfunction or damage of the unit
and also injury or damage to the surroundings.
7. Perform installation carefully according to the installation instructions of this
instruction manual.
8. Do not disassemble or alter this device. Also, do not remodel this device by
adding new functions. Contact the manufacturer for repairs.
9. Perform operation of the switches carefully according to the operation
instructions of this instruction manual. Incorrect operation may cause
malfunction.
10. Since this device is a precision electronic instrument, keep this device as
far away from noise source as possible. Also, remove noise from power
source of this device by using noise filter, etc.
11. For applications where serious damage or accidents may occur due to
malfunction or failure of this product, use several units to configure
various protection circuits according to the degree of seriousness of such
damage or accidents, such as "1 out of 2", "2 x (1 out of 2)", "2 out of 3",
etc.
*
Please do not use this device if its breakdown or malfunction may threaten
human life directly or it may harm human body.
Warning
！
Warning
！
Caution
！

TY-GC31-004A 2/24
Rev.B
Please note that NAGANO KEIKI does not take responsibility for damage or physical injury
caused by the followings:
Repairs or alterations by other companies.
Damage caused by any product of other companies.
Alterations, repairs or maintenance using non-authorized repair parts.
Misusage which does not follow the cautions, operation conditions, instructions specified in
this manual.
Fire, earthquake, water damage or other natural disaster.
Contents
1. Specifications･･･････････････････････････････････････････････ 3
2. Outline drawing･･･････････････････････････････････････････････ 5
3. Bracket/Panel Adaptor(Option)････････････････････････････････ 7
4. Mounting････････････････････････････････････････････ 8
5. Connection ････････････････････････････････････････････････ 10
6. Noise prevention･････････････････････････････････････････････ 13
7. Storage location･･･････････････････････････････････････････ 13
8. Maintenance ･･･････････････････････････････････････ 13
9. How to move to each mode ･･････････････････････････････････ 14
10. Function setting mode ･･････････････････････････ 15
11. Comparator setting mode / Loop check mode ･･･････････････ 18
12. Comparator operation･････････････････････････････････････ 20
13. Other functions････････････････････････････････････････ 22
14. Troubleshooting･････････････････････････････････････ 24

TY-GC31-004A 3/24
Rev.B
1. Specifications
Pressure range -100 ～100 kPa (100)
(Max. pressure -100 ～500 kPa (500)
display digit) 0 ～1.0 MPa -0.1 ～1.0 MPa (1.000)
0 ～2.0 MPa -0.1 ～2.0 MPa (2.00)
0 ～3.5 MPa (3.50)
0 ～5 MPa (5.00)
0 ～10 MPa (10.00)
0 ～20 MPa (20.0)
0 ～35 MPa (35.0)
0 ～50 MPa (50.0)
Display range From -10 to 110 %F.S. of the pressure range or from -1999 to 1999
(display value)
Max allowable Two times of pressure range (less than 35 MPa)
environment 1.5 times of pressure range (35 MPa or higher)
Applicable liquid Air, water, and oil, etc.. (Non-corrosive gas/liquid)
Environment used Under normal conditions, do not use a location where flammable or
Explosive gasses or liquids are present.
Connecting screw *1 R1/8 (with M5 female screw) Range: less than 1MPa
R1/4, G1/4B
Accuracy Display accuracy ±(1.0 %F.S. + 1 digit) at 23 ℃
Temperature characteristic ±0.1 %F.S./ ℃(Both zero and span)
Power source 12 - 24 VDC ±10% Ripple voltage : 10%(P-P) or lower
Current consumption Less than 30m ADC (Not including current of comparator output)
Display Pressure display 3 1/2 digit LED (Height of characters : 10 mm)
Operation display Red LED X 2 (Lit when turned ON)
Display cycle 0.2 s
Output Comparator output *1
NPN open collector ×2 outputs
PNP open collector ×2 outputs
Response Less than 5 ms
Output NPN 30 VDC, 80 mA max.
capacity PNP 24 VDC (Range of supply voltage),
80 mA max.
Dead band. Hysteresis :variable
Window comparator :1%F.S. Fixed
Delay 0.00～2.00 s (Both ON /OFF)

TY-GC31-004A 4/24
Rev.B
Analog output
1 - 5 VDC, 1 output
Output accuracy : ±1.5 %F.S. (for indication)
Response :Less than 50 ms
Resolution :Approx. 30 mV DC
Load resistance :10 kΩmin.
Heat run time More than 15 min.
Operating -10 to 50 ℃, 35 to 85 %RH (No condensation / freezing allowed)
temperature range
Storage -20 to 60 ℃, 35 to 85 %RH (No condensation / freezing allowed)
temperature range
Withstand voltage 300 VAC, 1 min.
Case construction IP 40 (For interior use)
Case material Front case part : PC/ABS
Rear case part : ADC 12
Wetted part material Sensor part : SUS 630 (17-4 PH)
Fitting part : SUS 304
Mounting clamp Key / L-shaped bracket : SPCC (t1.6)
material(Option) Panel adaptor : PC/ABS *2
Cable Length 2 m
Conductor :0.18 sq (7/0.18), Coated outer diameter : 0.86(㎜)
Sheath :Outer diameter : 4(㎜), Material: PVC
Weight Approx. 120g (Including 2 m cable)
EMC Directive *3 Applicable directive 89/336/EEC
Applicable standards
EN61326:1997/A1:1998/A2:2001/A3:2003
*1 Factory default
*2 For horizontal mounting only (GC31-3□4). Vertical mounting (GC31-1□4) is not
available.
*3 Please connect this unit to indoor distribution network which is free from any
overvoltage such as thunder, etc.

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Rev.B
2.Outline drawing
Vertical mounting
[GC31-124]
[GC31-164] [GC31-174]

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Rev.B
Horizontal mounting
[GC31-324]
[GC31-364] [GC31-374]

TY-GC31-004A 7/24
Rev.B
3.Brachket / Panel adaptor (Option)
L-shaped bracket
Key-shaped bracket
Panel adaptor (For horizontal mounting only)

TY-GC31-004A 8/24
Rev.B
4. Mounting
For mounting, select a location where there is no vibration or direct sunlight. Avoid moisture,
particles, oil and water, etc.
●Piping
When mounting R1/8 and R1/4 screw parts, hang a spanner (Width of 2 sides :17 mm) on
metallic hex part so that no excessive force is applied to main body (resin). Mounting torque shall
be 8N・m or lower. Also, make sure to wrap it with seal tape so that there will be no leakage.
For mounting of M5 screw, perform it as the description above. For mounting torque and
leak treatment, follow the instructions of the fitting.
●L / Key-shaped bracket (Option)
For L / Key-shaped bracket, use M3 sems screw. Mounting torque shall be 0.3 N・m or lower.
L-shaped bracket
Key-shaped bracket

TY-GC31-004A 9/24
Rev.B
●Panel adaptor (Option for horizontal mounting only)
Insert the adaptor 2 from the front side of main body in the direction shown below.
Insert the adaptor 1 from the obverse side of the panel cutout and insert the main body form
the reverse side of panel cutout. Then fix the snaps of adaptor 1 onto the main body. Insert
the adaptor 2 from the back side of the main body which is fixed to the adaptor 1. Push it until
the gap between panel surface and the adaptor becomes minimum.

TY-GC31-004A 10/24
Rev.B
5. Connection
Wiring
The cabling wire colors are as shown below. Power on after checking connection. After turned
on, to make sure that the system is stable enough, wait at least 5 minutes before performing
the zero point adjustment or measurement.
・Brown ……...… Power (+)
・Blue ……..….…Power (-)・COM
・Orange ………. Analog output (+)
・Black ……… …Open collector output OUT 1 (+)
・White ……… …Open collector output OUT2 (+)
Internal system
In output system, NPN open collector and PNP open collector (optional) are available for
comparator output. For analog output, 1 - 5 VDC voltage output is available.
a. Example of analog output wiring

TY-GC31-004A 11/24
Rev.B
b. Example of NPN open collector usage 1(Wiring to relay)
c. Example of NPN open collector usage 2 (Wiring to photo coupler)
d. Example of NPN open collector usage 3 (Voltage output)

TY-GC31-004A 12/24
Rev.B
e. Example of PNP open collector usage 1(Wiring to relay)
f. Example of PNP open collector usage 2 (Wiring to photo coupler)
g. Example of PNP open collector usage 3 （Voltage output）

TY-GC31-004A 13/24
Rev.B
6. Noise prevention
Power line
If noise remains in the power line, it may cause malfunctions such as fluctuation of display. Take
care not to tangle the AD/DC power line. Also, use a stable power source that has high noise
rejection ratio and will not cause ripple voltage.
Output routing
In the open collector output circuit, since output line and internal circuit are connected directly,
pay attention not to tangle lines. Also, make connection cables as short as possible.
Induction noise
Induction noise from outside sources may cause malfunctions. In this case, separate the device
from the noise source, change direction, and use a magnetic shield or an electrostatic shield.
Lightning surge
Lightning surge may cause malfunctions. Please connect this unit to indoor distribution network
which is free from influence of lightning surge.
Noise issues are complicated and many of them cannot be solved easily. If measured values
often fluctuate or differ, they may be affected by noise In this case, take noise prevention
measures described above.
7. Storage location
Do not store this device in the following places as it may cause malfunction and
damage.
Any place that water can reach.
Any place where there can be negative influence of atmosphere, temperature,
humidity, sunlight, dust, salt or sulphuric air.
Any places where there is vibration or shock (including during transportation).
Any place where chemicals are stored or where there are releases of gas.
In direct sunlight or inside a hot vehicle.
8. Maintenance
In this unit, there are no moving parts in the sensing element and circuit components so
basically there will be no maladjustment. However, depending on the use condition, aging may
occur so biannual regular check is recommended. For the zero point adjustment, perform it
following the instructions of zero point adjustment herein.
Since plastic molding material is used for the case part of this device, make sure not to touch it
with soldering iron, etc. Also, chemicals may have an adverse effect on the case so ensure
that none come in contact.
Caution
！

TY-GC31-004A 14/24
Rev.B
9. How to move to each mode
Each mode and its function
Pressing the
MODE
key for 3 seconds displays “---”. To return to measurement mode from
each setting mode, hold down the key for 3 seconds or more then “---” will flash.
Names on Panel and functions
Do not use sharp objects to press the keys as this can put holes in the panel.

TY-GC31-004A 15/24
Rev.B
10. Function setting mode
Setup steps
Pressing the
MODE
key for 3 seconds displays “---” and changes to function setting mode.
The setting mode is used to select comparator operation,
pressure unit, indication scaling, scaling of analog output,
and filter time constant.
Edit of the setting value in function setting mode recalculates all of the setting values including
the comparator. Please note that when the recalculated setting values are out of the display
range, they will be adjusted to the upper or lower limit value that can be processed internally.

TY-GC31-004A 16/24
Rev.B
Comparator operation selection
Select “Comparator Operation Selection” with the key. The message is
displayed for 1 sec. and then the current setting is displayed. Select either hysteresis or
window comparator operation mode with the ▲▼keys. Note that this device has 2 points
for comparator output. However, both points become same operation mode.
Display selection
Select “Display Selection” with the key. The message is displayed for 1
sec. and then the current setting is displayed. Select pressure display from either SI unit (Pa or
kPa) or display scaling with the ▲▼keys.
Scaling of LED display
When is selected in “Display Selection”, the LED display value for applied pressure
is displayed as an arbitrary scaling display. This is a function to scale the LED display value for
the min/max pressure value. It has no effect on the relation between the applied pressure and
analog output.
Use the key to set "Decimal point position", "Minimum pressure range display value"
and "Maximum pressure range display value" of "Display scaling".
1. After is displayed for 1 second, the current decimal point position is displayed.
Use ▲▼keys to set the decimal point position.
2. After is displayed for 1 second, the current display value of minimum pressure
range is displayed. Use ▲▼keys to set the display value.
3. After is displayed for 1 second, the current display value of maximum pressure
range is displayed. Use ▲▼keys to set the display value.
Follow the description above to perform the LED display setting.
Example) For the pressure range from 0.00 to 5.00 MPa (0 to 100 %F.S.), set display
scaling from 0.0 to 100.0.
: 0.02 0.1
Minimum pressure range value : 0.00 0.0
Maximum pressure range value : 5.00 100.0
MODE
MODE
Dec. point position
(from least significant digit)
MODE

TY-GC31-004A 17/24
Rev.B
Filter selection
This device is equipped with 5 internal time constant filters.
Select “Filter Selection” with the
MODE
key. The message is displayed for 1 sec.
and then the current setting mode is displayed. Select a time constant filter with the ▲▼keys.
Nofilter
Timeconstant:25ms
Time constant : 250ms
Timeconstant:2.5s
Timeconstant:5s
Timeconstant:10s
Use this function when pressure fluctuation is sharp and display, comparator output and analog
output are unstable.
The selected time constant filter is reflected on comparator/analog output as well.
Analog output scaling
This function sets the pressure values for analog output zero point (1VDC)/analog output span
point (5VDC) as a percentage (Where pressure range is from 0.0 to 100.0%F.S).
Use key to display setting of [Analog output zero point] / [Analog output span point].
1. After is displayed for 1 second, the current pressure value setting for analog
output zero point (1V) of analog output scaling. is displayed as a percentage (Where
pressure range is from 0.0 to 100.0%F.S). With ▲▼keys, set a pressure value as a
percentage.
2. After is displayed for 1 second, the current pressure value setting for analog
output span point (5V) of analog output scaling. is displayed as a percentage (Where
pressure range is from 0.0 to 100.0%F.S). With ▲▼keys, set a pressure value as a
percentage.
Analog output scaling is set by following the procedures described above.
Example) When analog output is 1～5 VDC for the pressure range 0.00 - 5.00MPa (0.0
～100.0%F.S.), perform scaling so that it will be "Analog output is 1～5 VDC for the
pressure range 0.00 - 4.91MPa (0.0～98.1%F.S.)".
Pressure value for analog output zero point 0.0 →0.0 (%F.S.)
Pressure value for analog output span point 100.0 →98.1 (%F.S.)
MODE

TY-GC31-004A 18/24
Rev.B
11. Comparator setting mode / Loop check mode
Setup steps
In measurement mode press the key (release within 3 secs.) to change to Comparator
setting mode / Loop check mode.
Comparator setting mode sets comparator output. This device is equipped with 2 points of
comparator output. In this mode, the content of setting items differs depending on the common
operation selected in both output 1/2 in the [Comparator operation selection] of function setting
mode.
In "Hysteresis", the settings of comparator operation point (A) and dead band (b) can be
performed for output 1/2 independently. In "Window comparator", the settings of comparator
operation point (A) and comparator operation point (B) can also be performed for output 1/2
independently. However, for the dead band in "Window comparator", 1%F.S. is fixed
automatically for the direction in which comparator is turned OFF. Also, for the common setting
of comparator operation, delay time setting where comparator operation is ON, delay time
setting where comparator operation is OFF can be performed for output 1/2 independently at
0.00 - 2.00 second.
In the Loop check mode, displayed pressure value can be changed by ▲▼keys regardless
of applied pressure. Comparator output and analog output are displayed according to this
pressure value. By performing above, output and output setting can be confirmed manually.
This operation can be used for simulation work of wiring check, etc.
MODE

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Rev.B