Vega VEGAVIB 61 User manual

Operating Instructions
Vibrating level switch for granulated bulk
solids
VEGAVIB 61
Contactless electronic switch
Document ID: 29266

2
Contents
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
Contents
1 About this document ............................................................................................................... 4
1.1 Function ........................................................................................................................... 4
1.2 Target group ..................................................................................................................... 4
1.3 Symbols used................................................................................................................... 4
2 For your safety ......................................................................................................................... 5
2.1 Authorised personnel ....................................................................................................... 5
2.2 Appropriate use................................................................................................................ 5
2.3 Warning about incorrect use............................................................................................. 5
2.4 General safety instructions............................................................................................... 5
2.5 Safety label on the instrument .......................................................................................... 6
2.6 Conformity........................................................................................................................ 6
2.7 SIL conformity .................................................................................................................. 6
2.8 Installation and operation in the USA and Canada ........................................................... 6
2.9 Safety instructions for Ex areas ........................................................................................ 6
2.10 Environmental instructions ............................................................................................... 6
3 Product description ................................................................................................................. 7
3.1 Conguration.................................................................................................................... 7
3.2 Principle of operation........................................................................................................ 7
3.3 Adjustment ....................................................................................................................... 8
3.4 Storage and transport....................................................................................................... 8
4 Mounting................................................................................................................................. 10
4.1 General instructions ....................................................................................................... 10
4.2 Mounting instructions ..................................................................................................... 11
5 Connecting to power supply................................................................................................. 15
5.1 Preparing the connection ............................................................................................... 15
5.2 Connection procedure.................................................................................................... 16
5.3 Wiring plan, single chamber housing.............................................................................. 16
6 Setup ....................................................................................................................................... 19
6.1 General information........................................................................................................ 19
6.2 Adjustment elements...................................................................................................... 19
6.3 Function table................................................................................................................. 20
7 Maintenanceandfaultrectication...................................................................................... 22
7.1 Maintenance .................................................................................................................. 22
7.2 Rectify faults................................................................................................................... 22
7.3 Exchanging the electronics module................................................................................ 23
7.4 How to proceed if a repair is necessary.......................................................................... 24
8 Dismount................................................................................................................................. 26
8.1 Dismounting steps.......................................................................................................... 26
8.2 Disposal ......................................................................................................................... 26
9 Supplement ............................................................................................................................ 27
9.1 Technical data ................................................................................................................ 27
9.2 Dimensions .................................................................................................................... 30
9.3 Industrial property rights................................................................................................. 32
9.4 Trademark ...................................................................................................................... 32

3
Contents
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
Safety instructions for Ex areas:
TakenoteoftheExspecicsafetyinstructionsforExapplications.
These instructions are attached as documents to each instrument
with Ex approval and are part of the operating instructions.
Editing status: 2022-09-15

4
1 About this document
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
1 About this document
1.1 Function
This instruction provides all the information you need for mounting,
connection and setup as well as important instructions for mainte-
nance,faultrectication,theexchangeofpartsandthesafetyofthe
user. Please read this information before putting the instrument into
operation and keep this manual accessible in the immediate vicinity
of the device.
1.2 Target group
This operating instructions manual is directed to trained personnel.
Thecontentsofthismanualmustbemadeavailabletothequalied
personnel and implemented.
1.3 Symbols used
Document ID
This symbol on the front page of this instruction refers to the Docu-
ment ID. By entering the Document ID on www.vega.com you will
reach the document download.
Information, note, tip: This symbol indicates helpful additional infor-
mation and tips for successful work.
Note: This symbol indicates notes to prevent failures, malfunctions,
damage to devices or plants.
Caution: Non-observance of the information marked with this symbol
may result in personal injury.
Warning: Non-observance of the information marked with this symbol
may result in serious or fatal personal injury.
Danger: Non-observance of the information marked with this symbol
results in serious or fatal personal injury.
Ex applications
This symbol indicates special instructions for Ex applications.
• List
The dot set in front indicates a list with no implied sequence.
1 Sequence of actions
Numbers set in front indicate successive steps in a procedure.
Disposal
This symbol indicates special instructions for disposal.

5
2 For your safety
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
2 For your safety
2.1 Authorised personnel
All operations described in this documentation must be carried out
onlybytrained,qualiedpersonnelauthorisedbytheplantoperator.
During work on and with the device, the required personal protective
equipment must always be worn.
2.2 Appropriate use
The VEGAVIB 61 is a sensor for point level detection.
Youcannddetailedinformationabouttheareaofapplicationin
chapter " Product description".
Operational reliability is ensured only if the instrument is properly
usedaccordingtothespecicationsintheoperatinginstructions
manual as well as possible supplementary instructions.
For safety and warranty reasons, any invasive work on the device
beyond that described in the operating instructions manual may be
carried out only by personnel authorised by the manufacturer. Arbi-
traryconversionsormodicationsareexplicitlyforbidden.
2.3 Warning about incorrect use
Inappropriate or incorrect use of this product can give rise to applica-
tion-specichazards,e.g.vesseloverllthroughincorrectmounting
or adjustment. Damage to property and persons or environmental
contamination can result. Also, the protective characteristics of the
instrument can be impaired.
2.4 General safety instructions
This is a state-of-the-art instrument complying with all prevailing
regulations and directives.The instrument must only be operated in a
technicallyawlessandreliablecondition.Theoperatorisresponsi-
ble for the trouble-free operation of the instrument.When measuring
aggressive or corrosive media that can cause a dangerous situation
if the instrument malfunctions, the operator has to implement suitable
measures to make sure the instrument is functioning properly.
The safety instructions in this operating instructions manual, the na-
tional installation standards as well as the valid safety regulations and
accident prevention rules must be observed by the user.
For safety and warranty reasons, any invasive work on the device
beyond that described in the operating instructions manual may be
carried out only by personnel authorised by the manufacturer. Arbi-
traryconversionsormodicationsareexplicitlyforbidden.Forsafety
reasons,onlytheaccessoryspeciedbythemanufacturermustbe
used.
To avoid any danger, the safety approval markings and safety tips on
the device must also be observed.

6
2 For your safety
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
2.5 Safety label on the instrument
The safety approval markings and safety tips on the device must be
observed.
2.6 Conformity
The device complies with the legal requirements of the applicable
country-specicdirectivesortechnicalregulations.Weconrmcon-
formity with the corresponding labelling.
The corresponding conformity declarations can be found on our
homepage.
2.7 SIL conformity
VEGAVIB 61 meets the requirements of functional safety according
to IEC 61508. Further information is available in the Safety Manual "
VEGAVIB series 60".
2.8 Installation and operation in the USA and
Canada
This information is only valid for USA and Canada. Hence the follow-
ing text is only available in the English language.
Installations in the US shall comply with the relevant requirements of
the National Electrical Code (ANSI/NFPA 70).
Installations in Canada shall comply with the relevant requirements of
the Canadian Electrical Code.
2.9 Safety instructions for Ex areas
For applications in explosion-proof areas (Ex), only devices with cor-
respondingExapprovalmaybeused.ObservetheEx-specicsafety
instructions.These are an integral part of the operating instructions
and are enclosed with every device with Ex approval.
2.10 Environmental instructions
Protection of the environment is one of our most important duties.
That is why we have introduced an environment management system
with the goal of continuously improving company environmental pro-
tection.Theenvironmentmanagementsystemiscertiedaccording
to DIN EN ISO 14001.
Pleasehelpusfullthisobligationbyobservingtheenvironmental
instructions in this manual:
• Chapter " Packaging, transport and storage"
• Chapter " Disposal"

7
3 Product description
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
3 Product description
3.1 Conguration
The scope of delivery encompasses:
• VEGAVIB 61 point level switch
• Documentation
– This operating instructions manual
– Safety Manual " Functional safety (SIL)" (optional)
– Supplementary instructions manual " Plug connector for level
sensors" (optional)
– Ex-specic"Safety instructions" (with Ex versions)
– Ifnecessary,furthercerticates
The VEGAVIB 61 consists of the components:
• Housing lid
• Housing with electronics
• Processttingwithvibratingrod
1
2
3
Fig. 1: VEGAVIB 61 with plastic housing
1 Housing lid
2 Housing with electronics
3 Processtting
Thetypelabelcontainsthemostimportantdataforidenticationand
use of the instrument:
• Article number
• Serial number
• Technical data
• Article numbers, documentation
• SILidentication(withSILratingexworks)
With the serial number, you can access the delivery data of the instru-
ment via " www.vega.com", " Search".Youcanndtheserialnumber
on the inside of the instrument as well as on the type label on the
outside.
3.2 Principle of operation
VEGAVIB 61 is a point level sensor with vibrating rod for point level
detection.
It is designed for industrial use in all areas of process technology and
is preferably used for bulk solids.
Scope of delivery
Constituent parts
Type label
Application area

8
3 Product description
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
Typicalapplicationsareoverllanddryrunprotection.Thankstoits
simple and robust measuring system, VEGAVIB 61 is virtually unaf-
fected by the chemical and physical properties of the bulk solid.
It also works when subjected to strong external vibrations or changing
products.
Solid detection in water
If VEGAVIB 61 was ordered for solid detection in water, the vibrating
rod is calibrated to the density of water. If covered by water (density:
1 g/cm³/0.036 lbs/in) VEGAVIB 61 signals "uncovered". Only if the
vibrating element is also covered with solids (e.g. sand, sludge, gravel
etc.) will the sensor signal "covered".
In this application case, the sensor should always be covered by
water for an empty message.
Function monitoring
The electronics module of VEGAVIB 61 continuously monitors the
following criteria:
• Correct vibrating frequency
• Linebreaktothepiezodrive
If one of the stated malfunctions is detected or in case of voltage
supply,theelectronicstakesonadenedswitchingstatus,i.e.the
contactless electronic switch opens (safe state).
Thevibratingrodispiezoelectricallyenergisedandvibratesatits
mechanicalresonancefrequencyofapprox.360Hz.Whenthevibrat-
ing rod is submerged in the product, the vibration amplitude changes.
This change is detected by the integrated electronics module and
converted into a switching command.
VEGAVIB 61 is a compact instrument, i.e. it can be operated without
external evaluation system.The integrated electronics evaluates the
level signal and outputs a switching signal.With this switching signal,
a connected device can be operated directly (e.g. a warning system,
a pump etc.).
Thedataforpowersupplyarespeciedinchapter"Technical data".
3.3 Adjustment
Ontheelectronicsmoduleyouwillndthefollowingdisplayand
adjustment elements:
• Signal lamp for indication of the switching condition (green/red)
• Potentiometer for adaptation to the product density
• Mode switch for selecting the switching condition (min./max.)
3.4 Storage and transport
Your instrument was protected by packaging during transport. Its
capacity to handle normal loads during transport is assured by a test
based on ISO 4180.
Functional principle
Voltage supply
Packaging

9
3 Product description
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
The packaging of standard instruments consists of environment-
friendly, recyclable carton material. The sensing element is additional-
ly protected with a cardboard cover. For special versions, PE foam or
PE foil is also used. Please dispose of the packaging material through
specialised recycling companies.
Transport must be carried out in due consideration of the notes on the
transport packaging. Nonobservance of these instructions can cause
damage to the device.
The delivery must be checked for completeness and possible transit
damage immediately at receipt. Ascertained transit damage or con-
cealed defects must be appropriately dealt with.
Up to the time of installation, the packages must be left closed and
stored according to the orientation and storage markings on the
outside.
Unless otherwise indicated, the packages must be stored only under
the following conditions:
• Not in the open
• Dry and dust free
• Not exposed to corrosive media
• Protected against solar radiation
• Avoiding mechanical shock and vibration
• Storage and transport temperature see chapter " Supplement -
Technical data - Ambient conditions"
• Relative moisture 20 … 85 %
With instrument weights of more than 18 kg (39.68 lbs) suitable and
approved equipment must be used for lifting and carrying.
Transport
Transport inspection
Storage
Storage and transport
temperature
Lifting and carrying

10
4 Mounting
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
4 Mounting
4.1 General instructions
Note:
For safety reasons, the instrument must only be operated within the
permissibleprocessconditions.Youcannddetailedinformationon
the process conditions in chapter " Technical data" of the operating
instructions or on the type label.
Hence make sure before mounting that all parts of the instrument ex-
posed to the process are suitable for the existing process conditions.
These are mainly:
• Active measuring component
• Processtting
• Process seal
Process conditions in particular are:
• Process pressure
• Process temperature
• Chemical properties of the medium
• Abrasionandmechanicalinuences
The instrument is suitable for standard and extended ambient condi-
tions acc. to DIN/EN/IEC/ANSI/ISA/UL/CSA 61010-1. It can be used
indoors as well as outdoors.
In general, VEGAVIB 61 can be installed in any position. The instru-
ment only has to be mounted in such a way that the vibrating element
is at the height of the desired switching point.
Use the recommended cables (see chapter " Connecting to power
supply") and tighten the cable gland.
You can give your instrument additional protection against moisture
penetration by leading the connection cable downward in front of the
cablegland.Rainandcondensationwatercanthusdraino.This
applies mainly to outdoor mounting as well as installation in areas
where high humidity is expected (e.g. through cleaning processes) or
on cooled or heated vessels.
To maintain the housing protection, make sure that the housing lid is
closed during operation and locked, if necessary.
Process conditions
Suitability for the ambient
conditions
Switching point
Moisture

11
4 Mounting
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
Fig. 2: Measures against moisture ingress
Do not hold VEGAVIB 61 on the vibrating element. Especially with
angeandtubeversions,thesensorcanbedamagedbytheweight
of the instrument.
Remove the protective cover just before mounting.
Theprocessttingmustbesealedifthereisgaugeorlowpressure
in the vessel. Before use, check if the sealing material is resistant
against the measured product and the process temperature.
Themax.permissiblepressureisspeciedinchapter"Technical
data" or on the type label of the sensor.
The vibrating level switch is a measuring instrument and must be
treated accordingly. Bending the vibrating element will destroy the
instrument.
Warning:
The housing must not be used to screw the instrument in! Applying
tightening force can damage internal parts of the housing.
Use the hexagon above the thread for screwing in.
Metric threads
In the case of instrument housings with metric thread, the cable
glands are screwed in at the factory. They are sealed with plastic
plugs as transport protection.
You have to remove these plugs before electrical connection.
NPT thread
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory. The
free openings for the cable glands are therefore covered with red dust
protection caps as transport protection.
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
4.2 Mounting instructions
The vibrating element should protrude into the vessel to avoid
buildup.Forthatreason,avoidusingmountingbossesforanges
Transport
Pressure/Vacuum
Handling
Cable entries - NPT
thread
Cable glands
Nozzle

12
4 Mounting
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
andscrewedttings.Thisappliesparticularlytousewithadhesive
products.
Mount the instrument in such a way that the vibrating rod does not
protrudedirectlyintothellingstream.
20°
a. b.
Fig. 3: Horizontal installation
a Protective sheet
b Concave protective sheet for abrasive solids
If such an installation location should be necessary, mount a suitable
protective sheet above or in front of the vibrating element, see illustra-
tion "a").
In abrasive solids, mounting according to illustration "b" has proven.
A spout forms in the concave protective sheet preventing wear of the
protective sheet.
In silos for bulk solids, material cones can form and change the
switching point. Please keep this in mind when installing the sensor
in the vessel.We recommend selecting an installation location where
the vibrating rod detects an average value of the material cone.
The vibrating rod must be mounted in a way that takes the arrange-
mentofthellingandemptyingaperturesintoaccount.
To compensate measurement errors caused by the material cone in
cylindrical vessels, the sensor must be mounted at a distance of d/6
from the vessel wall.
Filling opening
Material cone

13
4 Mounting
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
dd
d
6
d
6
Fig. 4: Filling and emptying centred
d
d
6
1
2
3
Fig. 5: Filling in the centre, emptying laterally
1 VEGAVIB 61
2 Discharge opening
3 Filling opening
To achieve a very precise switching point, you can install VEGAVIB 61
horizontally.However,iftheswitchingpointcanhaveatoleranceofa
Horizontal mounting

14
4 Mounting
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
few centimeters, we recommend mounting VEGAVIB 61 approx. 20°
inclined to the vessel bottom to avoid buildup.
20°
Fig. 6: Horizontal mounting
IfVEGAVIB61ismountedinthellingstream,unwantedfalsemeas-
urement signals can be generated. For this reason, mount VEGAVIB
61atapositioninthevesselwherenodisturbances,e.g.fromlling
openings, agitators, etc., can occur.
In applications such as grit chambers or settling basins for coarse
sediments, the vibrating element must be protected against damage
withasuitablebae.
Thisbaemustbemanufacturedbyyou.
> 125 mm
(> 5")
> 120 mm
(> 4.7")
Fig.7:Baeforprotectionagainstmechanicaldamage
Inowingmedium
Baeprotectionagainst
falling rocks

15
5 Connecting to power supply
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
Warning:
Connect only in the complete absence of line voltage.
• The electrical connection must only be carried out by trained,
qualiedpersonnelauthorisedbytheplantoperator.
• Alwaysswitchopowersupply,beforeconnectingordisconnect-
ing the instrument.
Note:
Install a disconnecting device for the instrument which is easy to
access.The disconnecting device must be marked for the instrument
(IEC/EN 61010).
Inhazardousareasyoumusttakenoteoftherespectiveregulations,
conformityandtypeapprovalcerticatesofthesensorsandpower
supply units.
Connect the voltage supply according to the connection diagrams.
The electronics module VB60C is designed in protection class I.
To maintain this protection class, it is absolutely necessary that the
earth conductor be connected to the inner earth conductor terminal.
Keep the general installation regulations in mind.Take note of the
correspondinginstallationregulationsforhazardousareaswithEx
applications.
Thedataforpowersupplyarespeciedinchapter"Technical data".
The instrument is connected with standard three-wire cable without
shielding. If electromagnetic interference is expected which is above
the test values of EN 61326 for industrial areas, shielded cable should
be used.
Make sure that the cable used has the required temperature resist-
anceandresafetyformax.occurringambienttemperature
Use cable with round cross-section. A cable outer diameter of
5…9mm(0.2…0.35in)ensuresthesealeectofthecablegland.
Ifyouareusingcablewithadierentdiameterorcross-section,
exchange the seal or use a suitable cable gland.
Inhazardousareas,useonlyapprovedcableconnectionsforVE-
GAVIB 61.
Take note of the corresponding installation regulations for Ex applica-
tions.
Cover all housing openings conforming to standard according to
EN 60079-1.
Note safety instructions
Take note of safety
instructions for Ex
applications
Voltage supply
Connection cable
Connection cable
for Ex applications

16
5 Connecting to power supply
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
5.2 Connection procedure
With Ex instruments, the housing cover may only be opened if there is
no explosive atmosphere present.
Proceed as follows:
1. Unscrew the housing lid
2. Loosen compression nut of the cable gland and remove blind
plug
3. Remove approx. 10 cm (4 in) of the cable mantle, strip approx.
1 cm (0.4 in) of insulation from the ends of the individual wires
4. Insert the cable into the sensor through the cable entry
5. Lift the opening levers of the terminals with a screwdriver (see
following illustration)
Fig. 8: Connection steps 5 and 6
6. Insert the wire ends into the open terminals according to the wir-
ing plan
7. Press down the opening levers of the terminals, you will hear the
terminal spring closing
8. Check the hold of the wires in the terminals by lightly pulling on
them
9. Tighten the compression nut of the cable entry gland. The seal
ring must completely encircle the cable
10. If necessary, carry out a fresh adjustment
11. Screw the housing lid back on
Theelectricalconnectionisnished.
5.3 Wiring plan, single chamber housing
The following illustrations apply to the non-Ex as well as to the Ex-d
version.

17
5 Connecting to power supply
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
1 2
4
3
5
5
55
Fig. 9: Material versions, single chamber housing
1 Plastic (not with Ex d)
2 Aluminium
3 Stainless steel (not with Ex d)
4 Stainless steel, electropolished (not with Ex d)
5 Filter element for pressure compensation (not with Ex d)
We recommend connecting VEGAVIB 61 in such a way that the
switching circuit is open when there is a level signal, line break or
failure (safe state).
The contactless electronic switch is always shown in non-operative
condition.
Warning:
The instrument must not be operated without an intermediately
connected load, because the electronics would be destroyed if con-
nected directly to the mains. It is not suitable for connection to low
voltage PLC inputs.
Examples for typical applications:
• Loadresistanceat24VDC:88…1800Ω
• Rated power, relay 253 V AC: > 2.5 VA
• Rated power, relay 24 V AC: > 0.5 VA
For direct control of relays, contactors, magnet valves, warning lights,
horns etc.
Domestic current is temporarily lowered below 1 mA after switching
otheloadsothatcontactors,whoseholdingcurrentislowerthan
the constant domestic current of the electronics, are reliably switched
o.
WhenVEGAVIB61isusedaspartofanoverllprotectionsystem
according to WHG, also note the regulations of the general type ap-
proval.
Housing overview
Wiring plan

18
5 Connecting to power supply
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
1
Fig. 10: Wiring plan
1 Shielding

19
6 Setup
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
6 Setup
6.1 General information
Theguresinbracketsrefertothefollowingillustrations.
Ontheelectronicsmoduleyouwillndthefollowingdisplayand
adjustment elements:
• Potentiometer for adjustment of the density range (1)
• DIL switch for mode adjustment - min./max. (2)
• Signal lamp (5)
Note:
As a rule, always set the mode with mode switch (2) before starting
the setup of VEGAVIB 61.The switching output will change if you set
the mode switch (2) afterwards.This could possibly trigger other con-
nected instruments or devices.
6.2 Adjustment elements
3
4
5
1
2
Fig. 11: Electronics and connection compartment - contactless electronic switch
1 Potentiometer for adjustment of the density range
2 DIL switch for mode adjustment
3 Ground terminal
4 Connection terminals
5 Control lamp
With the potentiometer you can adapt the switching point to the solid.
Itisalreadypresetandmustonlybemodiedinspecialcases.
As a default setting, the potentiometer of VEGAVIB 61 is set to the
complete right position (> 0.1 g/cm³ or 0.0036 lbs/in³). In very light
solids you have to turn the potentiometer to the complete left posi-
tion (0.02 … 0.1 g/cm³ or 0.0007 … 0.0036 lbs/in³). By doing this,
Function/Conguration
Electronics and connec-
tion compartment
Adjustment of the density
range (1)

20
6 Setup
VEGAVIB 61 • Contactless electronic switch
29266-EN-221012
VEGAVIB 61 will be more sensitive and light solids can be detected
more reliably.
For instruments detecting solids in water, these settings are not ap-
plicable.The density range is preset and must not be changed.
With the mode adjustment (min./max.) you can change the switching
condition of the output.You can set the required mode according to
the " Function table"(max.-max.detectionoroverowprotection,
min. - min. detection or dry run protection).
We recommend connecting according to the idle current principle
(contactless electronic switch is open when the switching point is
reached) because the contactless electronic switch takes on the
same (safe) state if a failure is detected.
Control lamp for indication of the switching status
• green = switch closed
• red = switch open
• red(ashing)=failure
6.3 Function table
The following table provides an overview of the switching conditions
depending on the set mode and the level.
Level Switching status Control lamp
Mode max.
Overowprotection
21
Switch closed Green
Mode max.
Overowprotection
21
Switch open Red
Mode min.
Dry run protection
21
Switch closed Green
Mode min.
Dry run protection
21
Switch open Red
Failure of the supply volt-
age
(min./max. mode)
any
21
Switch open
Mode adjustment (2)
Signal lamp (5)