SMC Networks ZK2-ZSV-A Series User manual

NO.ZK2-OM00501-B
PRODUCT NAME
Digital pressure switch for energy-saving
control ejector
MODEL / Series / Product Number
ZK2-ZSV####-A

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NO.ZK2-OM00501-B
Table of Contents
Safety Instructions 2
Model indication and How to order 9
Summary of Product parts 10
Definition and terminology 11
Wiring 15
Wiring 15
Internal circuit and wiring example 16
Mounting and Installation 17
Installation 17
Easy Setting 18
Measurement mode 18
Function Setting 22
Function selection mode 22
Default setting 22
F0 Unit selection function 24
F1 OUT1 25
F2 OUT2 27
F3 Response time 29
F4 Auto-preset 30
F6 Fine adjustment of display value 32
F11 Display resolution 33
F80 Power saving mode 34
F81 Security code 35
F90 Setting of all functions 36
F96 Check of suction command signal 38
F98 Check of output 39
F99 Reset to the default setting 41
Other Settings 42
How to stop energy-saving control function 45
Maintenance 46
Troubleshooting 47
Error indication 54
Specification 55
A
B

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NO.ZK2-OM00501-B
Safety Instructions
These safety instructions are intended to prevent hazardous situations and/or equipment damage.
These instructions indicate the level of potential hazard with the labels of "Caution", "Warning" or
"Danger". They are all important notes for safety and must be followed in addition to International
standards (ISO/IEC) 1) and other safety regulations.
1) ISO 4414: Pneumatic fluid power -- General rules relating to systems
ISO 4413: Hydraulic fluid power -- General rules relating to systems
IEC 60204-1: Safety of machinery -- Electrical equipment of machines (Part 1: General requirements)
ISO 10218-1992: Manipulating industrial robots -Safety.
etc.
Caution :
CAUTION indicates a hazard with a low level of risk which, if not avoided,
could result in minor or moderate injury.
Warning :
WARNING indicates a hazard with a medium level of risk which, if not
avoided, could result in death or serious injury.
Danger :
DANGER indicates a hazard with a high level of risk which, if not avoided,
will result in death or serious injury.
Warning
1. The compatibility of the product is the responsibility of the person who designs the
equipment or decides its specifications.
Since the product specified here is used under various operating conditions, its compatibility with
specific equipment must be decided by the person who designs the equipment or decides its
specifications based on necessary analysis and test results. The expected performance and safety
assurance of the equipment will be the responsibility of the person who has determined its
compatibility with the product.This person should also continuously review all specifications of the
product referring to its latest catalog information, with a view to giving due consideration to any
possibility of equipment failure when configuring the equipment.
2. Only personnel with appropriate training should operate machinery and equipment.
The product specified here may become unsafe if handled incorrectly.The assembly, operation and
maintenance of machines or equipment including our products must be performed by an operator
who is appropriately trained and experienced.
3. Do not service or attempt to remove product and machinery/equipment until safety is confirmed.
1.The inspection and maintenance of machinery/equipment should only be performed after measures
to prevent falling or runaway of the driven objects have been confirmed.
2.When the product is to be removed, confirm that the safety measures as mentioned above are
implemented and the power from any appropriate source is cut, and read and understand the
specific product precautions of all relevant products carefully.
3. Before machinery/equipment is restarted, take measures to prevent unexpected operation and
malfunction.
4. Contact SMC beforehand and take special consideration of safety measures if the product is
to be used in any of the following conditions.
1. Conditionsandenvironmentsoutside ofthe given specifications, oruse outdoorsor inaplace exposed
todirectsunlight.
2. Installationonequipment inconjunctionwithatomicenergy,railways,air navigation,space,shipping,
vehicles,military,medicaltreatment, combustionandrecreation,orequipmentincontact withfoodand
beverages,emergencystopcircuits, clutchandbrakecircuitsinpressapplications,safetyequipmentor
otherapplicationsunsuitableforthestandardspecificationsdescribedintheproductcatalog.
3.An application which could have negative effects on people, property, or animals requiring special
safetyanalysis.
4. Use in an interlock circuit, which requires the provision of double interlock for possible failure by
using a mechanical protective function, and periodical checks to confirm proper operation.

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NO.ZK2-OM00501-B
Caution
The product is provided for use in manufacturing industries.
The product herein described is basically provided for peaceful use in manufacturing industries.
If considering using the product in other industries, consult SMC beforehand and exchange
specifications or a contract if necessary.
If anything is unclear, contact your nearest sales branch.
Limited warranty and Disclaimer/Compliance Requirements
The product used is subject to the following "Limited warranty and Disclaimer" and "Compliance
Requirements".
Read and accept them before using the product.
Limited warranty and Disclaimer
1. The warranty period of the product is 1 year in service or 1.5 years after the product is delivered,
whichever is first. 2)
Also, the product may have specified durability, running distance or replacement parts. Please
consult your nearest sales branch.
2. For any failure or damage reported within the warranty period which is clearly our responsibility, a
replacement product or necessary parts will be provided.
This limited warranty applies only to our product independently, and not to any other damage
incurred due to the failure of the product.
3. Prior to using SMC products, please read and understand the warranty terms and disclaimers noted
in the specified catalog for the particular products.
2) Vacuum pads are excluded from this 1 year warranty.
A vacuum pad is a consumable part, so it is warranted for a year after it is delivered.
Also, even within the warranty period, the wear of a product due to the use of the vacuum pad or failure due to
the deterioration of rubber material are not covered by the limited warranty.
Compliance Requirements
1. The use of SMC products with production equipment for the manufacture of weapons of mass
destruction (WMD) or any other weapon is strictly prohibited.
2. The exports of SMC products or technology from one country to another are governed by the
relevant security laws and regulation of the countries involved in the transaction. Prior to the
shipment of a SMC product to another country, assure that all local rules governing that export are
known and followed.

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NO.ZK2-OM00501-B
Operator
This operation manual is intended for those who have knowledge of machinery using pneumatic
equipment, and have sufficient knowledge of assembly, operation and maintenance of such
equipment. Only those persons are allowed to perform assembly, operation and maintenance.
Read and understand this operation manual carefully before assembling, operating or providing
maintenance to the product.
■Safety Instructions
Warning
■Do not disassemble, modify (including changing the printed circuit board) or repair.
An injury or failure can result.
■Do not use the product except for energy-saving control ejector
Fire, malfunction, or damage to the product or the system can result.
■Do not operate the product outside of the specifications.
Do not use for flammable or harmful fluids.
Fire, malfunction, or damage to the product can result.
Verify the specifications before use.
■Do not operate in an atmosphere containing flammable or explosive gases.
Fire or an explosion can result.
This product is not designed to be explosion proof.
■Do not use the product in a place where static electricity is a problem.
Otherwise it can cause failure or malfunction of the system.
■If using the product in an interlocking circuit.
Provide a double interlocking system, for example a mechanical system
Check the product regularly for proper operation
Otherwise malfunction can result, causing an accident.
■The following instructions must be followed during maintenance.
Turn off the power supply
Stop the air supply, exhaust the residual pressure and verify that the air is released before performing
maintenance.
Otherwise an injury can result.
■Verify the system sufficiently before judging the applicability when a permeable workpiece is to be sucked.
Rapid decrease in vacuum pressure during suction of the workpiece may cause the ejector to fail to restart
in time, causing injury or damage to the system because of the suction failure.

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NO.ZK2-OM00501-B
Caution
■Do not touch the terminals and connectors while the power is on.
Otherwise electric shock, malfunction or damage to the product can result.
■Perform sufficient trial run.
Otherwise, injury or damage to the system can result due to suction failure depending on the conditions of
the suction of the workpiece or the pressure switch settings.
Perform sufficient verification before using this product.
■After maintenance is complete, perform appropriate functional inspections and leak test.
Stop operation if the equipment does not function properly or there is leakage of fluid.
If there is leakage from parts other than the piping, the product might be broken.
Cut off power supply and stop supplying fluid.
Do not supply fluid if there is leakage.
Safety cannot be assured in the case of unexpected malfunction.
■NOTE
○Follow the instructions given below when designing, selecting and handling the product.
●The instructions on design and selection (installation, wiring, environment, adjustment,
operation, maintenance, etc.) described below must also be followed.
Product specifications
Use the specified voltage.
Otherwise failure or malfunction can result.
Do not exceed the specified maximum allowable load.
Otherwise it can cause damage or shorten the lifetime of the Pressure switch.
Design the product to prevent reverse current when the circuit is opened or the product is forced to operate for
operational check.
Reverse current can cause malfunction or damage to the product.
Input data to the Pressure switch is not deleted, even if the power supply is cut off.
(Writing time: 1,000,000 times)
For the details of compressed air quality, refer to ISO 8573-1, 1.1.2 to 1.6.2: 2001.
This can cause operating failure.
If compressed air containing condensate is used, install an air dryer or drain catch before the filter and perform
drainage regularly.
If drainage is not performed regularly and condensate enters the secondary side, it can cause operating failure of
pneumatic equipment.
If regular drainage is difficult, the use of a filter with an auto drain is recommended.
Applicable fluid is air, inert gases and incombustible gases.
Do not use a fluid containing chemicals, synthetic oils including organic solvent, salt and corrosive gases.
Otherwise, damage to the product and malfunction can result.
Check the details of the specifications before using.
Use the specified measurement flow rate and operating pressure.
Otherwise it can cause damage to the pressure switch or inability to measure correctly.
Reserve a space for maintenance.
Allow sufficient space for maintenance when designing the system.

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NO.ZK2-OM00501-B
●Product handling
Installation
Tighten to the specified tightening torque.
If the tightening torque is exceeded the mounting screws and brackets may be broken.
If the tightening torque is insufficient, the product can be displaced and loosen the mounting screws.
(Refer to page 17)
Be sure to ground terminal FG when using a commercially available switch-mode power supply.
Do not drop, hit or apply excessive shock (over 100 m/s2) to the Pressure switch.
Otherwise damage to the internal parts can result, causing malfunction.
Do not pull the lead wire forcefully, not lift the product by pulling the lead wire. (Tensile force 20 N or
less)
Hold the body when handling to avoid the damage of the Pressure switch which lead to cause the failure and
malfunction.
Eliminate any dust left in the piping by air blow before connecting the piping to the product.
Otherwise it can cause damage or malfunction.
Do not insert metal wires or other foreign matter into the pressure measurement port.
It can damage the pressure sensor causing failure or malfunction.
Never mount a Pressure switch in a location that will be used as a foothold.
The product may be damaged if excessive force is applied by stepping or climbing onto it.
If the entering of foreign material to the fluid is possible, install and pipe the filter or the mist separator to
the inlet to avoid failure and malfunction.

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NO.ZK2-OM00501-B
Wiring
Do not pull the lead wires.
In particular, never lift a Pressure switch equipped with fitting and piping by holding the lead wires.
Otherwise damage to the internal parts can result, causing malfunction or to be off the connector.
Avoid repeatedly bending or stretching the lead wire, or placing heavy load on them.
Repetitive bending stress or tensile stress can cause the sheath of the wire to peel off, or breakage of the wire.
If the lead wire can move, fix it near the body of the product.
The recommended bend radius of the lead wire is 6 times the outside diameter of the sheath, or 33 times the
outside diameter of the insulation material, whichever is larger.
Replace the damaged lead wire with a new one.
Wire correctly.
Incorrect wiring can break the Pressure switch.
Do not perform wiring while the power is on.
Otherwise damage to the internal parts can result, causing malfunction.
Do not route wires and cables together with power or high voltage cables.
Otherwise the product can malfunction due to interference of noise and surge voltage from power and high voltage
cables to the signal line. Route the wires (piping) of the product separately from power or high voltage cables.
Confirm proper insulation of wiring.
Poor insulation (interference from another circuit, poor insulation between terminals, etc.) can lead to excess
voltage or current being applied to the product, causing damage.
Design the system to prevent reverse current when the product is forced to operate for operational
check.
Depending on the circuit used, insulation may not be maintained when operation is forced, allowing reverse current
to flow, which can cause malfunction and damage the product.
Keep wiring as short as possible to prevent interference from electromagnetic noise and surge voltage.
Do not use a cable longer than 10 m.
Wire the DC(-) line(blue) as close as possible to the power supply.
Environment
Do not use the product in area that is exposed to corrosive gases, chemicals, sea water, water or steam.
Otherwise failure or malfunction can result.
Do not use in a place where the product could be splashed by oil or chemicals.
If the product is to be used in an environment containing oils or chemicals such as coolant or cleaning solvent,
even for a short time, it may be adversely affected (damage, malfunction, or hardening of the lead wires).
Do not use in an area where surges are generated.
If there is equipment which generates a large amount of surge (solenoid type lifter, high frequency induction
furnace, motor, etc.) close to the Pressure switch, this may cause deterioration or breakage of the internal circuit of
the Pressure switch. Avoid sources of surge generation and crossed lines.
Do not use a load which generates surge voltage.
When a surge-generating load such as a relay or solenoid is driven directly, use a Pressure switch with a built-in
surge absorbing element.
The product is CE marked, but not immune to lightning strikes. Take measures against lightning strikes
in the system.
This product is CE marked, it may happen that the set value of product is changed by the noise impressed in
excess.
Mount the product in a place that is not exposed to vibration or impact.
Otherwise failure or malfunction can result.

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NO.ZK2-OM00501-B
Prevent foreign matter such as remnant of wires from entering the Pressure switch.
Take proper measures for the remnant not to enter the Pressure switch in order to prevent failure or malfunction.
Do not use the product in an environment that is exposed to temperature cycle.
Heat cycles other than ordinary changes in temperature can adversely affect the inside of the product.
Do not expose the product to direct sunlight.
If using in a location directly exposed to sunlight, shade the product from the sunlight.
Otherwise failure or malfunction can result.
Keep within the specified fluid and ambient temperatures range.
The fluid and ambient temperatures should be 5 to 50 oC. Operation under low temperature leads to cause damage
or operation failure due to frozen moist in the fluid or air.
Protection against freezing is necessary. Air dryer is recommended for elimination of drain and water.
Avoid sudden temperature change even within specified temperature.
Do not operate close to a heat source, or in a location exposed to radiant heat.
Otherwise malfunction can result.
Adjustment and Operation
Turn the power on after connecting a load.
Otherwise it can cause excess current causing instantaneous breakage of the Pressure switch.
Do not short-circuit the load.
Although error is displayed when the Pressure switch load is short circuit, generated excess current lead to cause
the damage of the Pressure switch.
Do not press the setting buttons with a sharp pointed object.
It may damage the setting buttons.
If using the product to detect very small pressure rates, warm up the product for 10 to 15 minutes first.
There will be a drift on the display of approximate 1% immediately after the power supply is turned on.
Perform settings suitable for the operating conditions.
Incorrect setting can cause operation failure.
For details of each setting, refer to page 21 to 45 of this manual.
The Pressure switch is compulsory turned off for 1 second after power supplied.
For 4 seconds after supplying power, the measurement output is turned off.
Maintenance
Turn off the power supply, stop the supplied air, exhaust the residual pressure and verify the release of
air before performing maintenance.
There is a risk of unexpected malfunction.
Perform regular maintenance and inspections.
There is a risk of unexpected malfunction.
Perform drainage regularly.
If condensate enters the secondary side, it can cause operating failure of pneumatic equipment.
Do not use solvents such as benzene, thinner etc. to clean the Pressure switch.
They could damage the surface of the body and erase the markings on the body.
Use a soft cloth to remove stains. For heavy stains, use a cloth soaked with diluted neutral detergent and fully
squeezed, then wipe up the stains again with a dry cloth.
A

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NO.ZK2-OM00501-B
Model Indication and How to order
How to order
Integrated cable assembly for the solenoid valve/pressure switch
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NO.ZK2-OM00501-B
Summary of Product parts
Output (OUT1) LED (green): LED is ON when the switch output (OUT1) is ON.
Output (OUT2) LED (Red): LED is ON when the supply pilot valve is ON.
LED display: Displays the current status of pressure, setting mode and error code.
button (UP): Selects a mode and increases ON/OFF set value.
Press this button to change to the peak display mode.
button (DOWN): Selects a mode and decreases ON/OFF set value.
Press this button to change to the bottom display mode.
button (SET): Press this button to change to another mode and to set a value.

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NO.ZK2-OM00501-B
■Definition and terminology
No.
Terms
Meaning
7
7-segment indication
Display type where each individual display character consists of up to 7 separate
sections (called segments)
(The figure “8” uses all 7 segments)
A
Adsorption directive signal
Indicate the command signal which generate vacuum.
(It is necessary to input the pressure switch)
Auto preset
A function of the Pressure switch to automatically setup pressure just by having
equipment hold and release a workpiece via vacuum adsorption. This function is
used in an application where vacuum adsorption of a workpiece needs to be
confirmed with a Pressure switch.
B
Bottom value display (mode)
Indicates the minimum vacuum pressure reached up to that moment.
C
Chattering
The problem of the switch output turning ON and OFF repeatedly around the set
value at high frequency due to the effect of pulsation.
Chattering-preventing function
Afunction to delay the response time of switch output in order to prevent
chattering.
D
Digit (Min. setting unit)
Shows how precisely the pressure can be indicated or set by the digital
Pressure switch. When 1 digit=1 kPa, the pressure is given with an increment of
1 kPa, e.g., 1, 2, 3,…, 99, 100.
E
Energy saving automatic
control
Indicate that the vacuum pressure during adsorption is monitored and ON and
OFF of the ejector is automatically controlled.
Error indication (Error code)
With the self-diagnosis function given to the Pressure switch, it indicates that
there is a failure which could cause a switch failure.
F
Fine adjustment mode
Refer to "Fine adjustment of display value".
Fine adjustment of display
value
An indicated pressure value can be adjusted within the range of ±5% R.D.
(±5% of the indicated value). It is used if a true pressure value is known or to
correct the difference of an indicated value of the measurement equipment
nearby that measures the same pressure as the Pressure switch.
F.S. (full span/full scale)
Abbreviation for full span and full scale; means the maximum fluctuation range
of the Pressure switch rated value.
Function selection mode
A mode in which setting of functions is performed. It is a separate menu from the
pressure setting.
If any function settings needs to be changed from the factory default, each setting
can be selected with “F ”.
The setting items are: display color, operation mode, output type, response time,
display resolution, display value fine adjustment, use of auto preset, use of power
saving mode, and use of PIN number. Refer to page 25 for a list of output
modes that can be selected.
H
Hysteresis
Difference between the points at which the Pressure switch is turned on and off.
Hysteresis mode
Refer to "List of output modes" on page 25
A

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NO.ZK2-OM00501-B
No.
Terms
Meaning
I
Indication accuracy
Shows the deviation between displayed pressure value and the true pressure.
Insulation resistance
Insulation resistance of the product.
The resistance between the electrical circuit and the case.
Indication resolution
How fine the rated pressure range can be segmented. (Example: If a product
for 0 to 1 MPa can indicate pressure by 0.001 MPa, the indication resolution is
1/1000.)
Indication LED
The LED that turns on when the switch output is ON.
Indication unit
The unit of pressure used in the display.
K
Key lock function
Function that prevents changes to the settings of the Pressure switch (disables
button operation).
M
Manual set up
Manual pressure setup without using auto preset.
This term is used to distinguish between manual and auto preset pressure
setup.
Max. applied voltage
The maximum value of applied voltage available to the output line of the NPN
output.
Max. (Min) load impedance
The maximum (minimum) load (resistance value and impedance) which can be
connected to the output (output line) of the analog current output.
Measurement mode
The condition in which the pressure is being detected and indicated and switch
operation is enabled.
Min. setting unit
Refer to "digit".
N
Normal output
One of the switch output types. In hysteresis mode the switch output is turned
ON when pressure equal to or greater than the switch output set value is
detected.
Refer to "List of output modes" on page 25)
NPN (open collector) (output)
The switch that uses the NPN transistor for output.
O
Output configuration
The operation principle of the switch output.
Refer to "List of output modes" on page 25 for the operation status.
Output mode
Either hysteresis mode can be selected.
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NO.ZK2-OM00501-B
No.
Terms
Meaning
P
Peak value display
Displays the maximum vacuum pressure reached up to that moment.
Pilot valve for air supply
The solenoid valve which turns on and off the ejector.
(This pressure switch outputs signal to the supply pilot valve)
PNP (open collector) (output)
The switch that uses the PNP transistor for output.
Power saving mode
The condition in which the indicated value turns off and current consumption is
reduced.
Pressure setting
The setting of pressure to determine the point at which the Pressure switch
turns on and off.
Proof pressure
Pressure limit that if exceeded will result in mechanical and/or electrical damage
to the product.
R
Rated pressure range
The pressure range in which the Pressure switch satisfies the specifications.
Values over this range can be set if they are within the set pressure range, but
cannot assured the specifications to be satisfied.
Repeatability
Reproducibility of the displayed value for pressure and ON-OFF output
operating point when the pressure changes at a temperature of 25 oC.
Residual voltage
The difference between the ideal ON voltage and the actual voltage when the
switch output is on. It depends on present load current and ideally should be
"0".
Resolution
See "Indication resolution".
Response time
The time from when the pressure applied to the pressure switch reaches the set
value, to when the ON-OFF output actually begins working. Generally, the
shorter the response time, the better the performance.
Reversed output(OUT1)
One of the switch output types. In hysteresis mode the switch output is turned
ON when pressure less than or equal to the switch output set value is detected.
(Refer to "List of output modes" on page 25)
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NO.ZK2-OM00501-B
No.
Terms
Meaning
S
Setting of function
Refer to "Function selection mode".
Setting pressure range.
The pressure range within which switch output can be set.
Switch output
Output type that only has 2 possible states, ON or OFF. Sometimes referred to
as "ON-OFF output".
U
Unit selection function
Function to change the unit in which the value of pressure is indicated. Only a
product with this function can change the unit. A product with unit-changing
function cannot be purchased if it is used within Japan. Pressure is indicated
only by SI units in Japan.
W
Withstand voltage
A measure of the product’s resistance to a voltage applied between the
electrical circuit and case.
The product may be damaged if a voltage over this value is applied.
(The withstand voltage is not the supply voltage used to power the product.)
Z
Zero clear (function)
Adjusts the displayed pressure value to "0".
A

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NO.ZK2-OM00501-B
Wiring
■Wiring
○Connection
Connections should only be made with the power supply turned off.
Use separate routes for the Pressure switch wiring and any power or high voltage wiring. Otherwise,
malfunction may result due to noise.
Ensure that the FG terminal is connected to ground when using a commercially available switch-mode
power supply. When a switch-mode power supply is connected to the product, switching noise will be
superimposed and the product specification can no longer be met. This can be prevented by inserting a
noise filter, such as a line noise filter and ferrite core, between the switch-mode power supply and the
product, or by using a series power supply instead of a switch-mode power supply.
○Connector use for pressure switch
Connecting/Disconnecting
When mounting the connector, insert it straight into the socket holding the lever and connector body, and
push the connector until the lever hooks into the housing, and locks.
When removing the connector, press down the lever to release the hook from housing and pull the
connector straight out.
Pin No. of the Connector (Power supply and output cable for the digital pressure switch and pilot
valve)

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NO.ZK2-OM00501-B
■Internal circuit and wiring example
NPN output type
NPN open collector 2 outputs, Max. applied voltage 26.4VDC, Max. load current 80mA
Residual voltage 2 V or less
PNP output type
PNP open collector 2 outputs, Max. load current 80mA, Residual voltage 2 V or less

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NO.ZK2-OM00501-B
Mounting and Installation
■Installation
Mount the O-ring provided into the O-ring groove of the pressure switch, and mount the pressure switch to
the ejector body with the two mounting screws provided. (The required tightening torque is 0.08 to 0.10 Nm)
If the tightening torque is exceeded, the mounting part can be deformed and broken.

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Easy Setting
■Measurement mode
The measurement mode is the condition where the pressure is detected and indicated, and the switch
function is operating.
This is the basic mode, and other modes should be selected for setting changes and other function settings.
A

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See below for the energy saving control operation and the set values which are preset to the switch.
If the operation shown below is acceptable, then keep these settings.
Function that enables the easy setting of the ON and OFF points of the switch output, and the operation of the
supply pilot valve.
Operation of OUT1
When the pressure exceeds the set value (P_1), the pressure switch will be turned ON.
When the pressure falls below the set value (P_1) by the amount of hysteresis value (H_1), the switch will be
turned OFF.
The default settings are P_1: -70.0 kPa and H_1:10.0 kPa.
Operation of OUT2
Supply pilot valve: OUT2 is turned on by the signal for suction. Suction starts by the generation of vacuum
pressure.
When the vacuum pressure reaches the set value (P_1), the supply pilot valve turns OFF.
After the supply pilot valve is turned off, the vacuum pressure will decrease, when the vacuum pressure drops
below (P_1) by the amount set in (P_2) the supply pilot valve will turn on again and increase the vacuum
pressure.
After that, supply pilot valve will turn ON and OFF repeatability.
Default setting is H_2: 5.0 kPa.