Vega VEGATOR 132 User manual

Operating Instructions
Double-channel signal conditioning
instrument for point level detection with
conductive sensors
VEGATOR 132
Document ID: 46837

2
Contents
VEGATOR 132 •
46837-EN-170907
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 EU conformity................................................................................................................... 6
2.6 Safety label on the instrument .......................................................................................... 6
2.7 Installation and operation in the USA and Canada ........................................................... 6
2.8 Safety instructions for Ex areas ........................................................................................ 6
2.9 Environmental instructions ............................................................................................... 6
3 Product description ................................................................................................................. 7
3.1 Conguration.................................................................................................................... 7
3.2 Principle of operation........................................................................................................ 7
3.3 Adjustment ....................................................................................................................... 8
3.4 Packaging, transport and storage..................................................................................... 8
4 Mounting................................................................................................................................... 9
4.1 Mounting instructions ....................................................................................................... 9
5 Connecting to power supply................................................................................................. 10
5.1 Preparing the connection ............................................................................................... 10
5.2 Connection procedure.................................................................................................... 11
5.3 Wiring plan ..................................................................................................................... 12
5.4 Wiring plan four-channel control..................................................................................... 13
6 Setup ....................................................................................................................................... 14
6.1 Adjustment system......................................................................................................... 14
6.2 Adjustment elements...................................................................................................... 14
6.3 Proof test........................................................................................................................ 17
6.4 Function table "Point level" ............................................................................................. 17
6.5 Function table, two-point control..................................................................................... 18
7 Maintenanceandfaultrectication...................................................................................... 21
7.1 Maintenance .................................................................................................................. 21
7.2 Rectify faults................................................................................................................... 21
7.3 How to proceed if a repair is necessary.......................................................................... 22
8 Dismount................................................................................................................................. 23
8.1 Dismounting steps.......................................................................................................... 23
8.2 Disposal ......................................................................................................................... 23
9 Supplement ............................................................................................................................ 24
9.1 Technical data ................................................................................................................ 24
9.2 Dimensions .................................................................................................................... 26
9.3 Industrial property rights................................................................................................. 27
9.4 Trademark ...................................................................................................................... 27

3
Contents
VEGATOR 132 •
46837-EN-170907
Supplementary documentation
Information:
Supplementary documents appropriate to the ordered version come
withthedelivery.Youcanndthemlistedinchapter"Product descrip-
tion".
Editing status: 2017-09-04

4
1 About this document
VEGATOR 132 •
46837-EN-170907
1 About this document
1.1 Function
This operating instructions manual provides all the information you
need for mounting, connection and setup of the instrument. Further-
morethereareimportantinstructionsformaintenance,faultrectica-
tion, 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 specialist
personnel.The contents of this manual should be made available to
these personnel and put into practice by them.
1.3 Symbols used
Information, tip, note
This symbol indicates helpful additional information.
Caution: If this warning is ignored, faults or malfunctions can result.
Warning: If this warning is ignored, injury to persons and/or serious
damage to the instrument can result.
Danger: If this warning is ignored, serious injury to persons and/or
destruction of the instrument can result.
Ex applications
This symbol indicates special instructions for Ex applications.
SIL applications
This symbol indicates instructions for functional safety which must be
taken into account particularly for safety-relevant applications.
• List
The dot set in front indicates a list with no implied sequence.
→ Action
This arrow indicates a single action.
1 Sequence of actions
Numbers set in front indicate successive steps in a procedure.
Battery disposal
This symbol indicates special information about the disposal of bat-
teries and accumulators.

5
2 For your safety
VEGATOR 132 •
46837-EN-170907
2 For your safety
2.1 Authorised personnel
All operations described in this operating instructions manual must
be carried out only by trained specialist 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
VEGATOR 132 is a universal signal conditioning instrument for con-
nection of conductive sensors.
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 the instrument can give rise to
application-specichazards,e.g.vesseloverllordamagetosystem
components through incorrect mounting or adjustment.Thus dam-
age to property, to persons or environmental contamination can be
caused. Also the protective characteristics of the instrument can be
inuenced.
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.
During the entire duration of use, the user is obliged to determine the
compliance of the necessary occupational safety measures with the
current valid rules and regulations and also take note of new regula-
tions.
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-

6
2 For your safety
VEGATOR 132 •
46837-EN-170907
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 and their meaning looked up in this
operating instructions manual.
2.5 EU conformity
ThedevicefullsthelegalrequirementsoftheapplicableEUdirec-
tives.ByaxingtheCEmarking,weconrmtheconformityofthe
instrument with these directives.
YoucanndtheEUconformitydeclarationonourwebsiteunder
www.vega.com/downloads.
2.6 Safety label on the instrument
The safety approval markings and safety tips on the device must be
observed.
2.7 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
2.8 Safety instructions for Ex areas
PleasenotetheEx-specicsafetyinformationforinstallationandop-
eration in Ex areas.These safety instructions are part of the operating
instructions manual and come with the Ex-approved instruments.
2.9 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
VEGATOR 132 •
46837-EN-170907
3 Product description
3.1 Conguration
The scope of delivery encompasses:
• VEGATOR 132 signal conditioning instrument
• Documentation
– This operating instructions manual
– Ex-specic"Safety instructions" (with Ex versions)
– Ifnecessary,furthercerticates
Thetypelabelcontainsthemostimportantdataforidenticationand
use of the instrument:
• Instrument type
• Product code
• Approvals
• Technical data
• Serial number of the instrument
• Data matrix code for VEGA Tools app
The type label contains the serial number of the instrument. With it
youcanndthefollowingdataonourhomepage:
• Product code of the instrument (HTML)
• Delivery date (HTML)
• Order-specicinstrumentfeatures(HTML)
• Operating instructions at the time of shipment (PDF)
• Safetyinstructionsandcerticates
Go to "www.vega.com", "Instrument search (serial number)". Enter
the serial number.
Alternatively, you can access the data via your smartphone:
• Download the "VEGA Tools" app from the "Apple App Store" or the
"Google Play Store"
• Scan the Data Matrix code on the type label of the instrument or
• Enter the serial number manually in the app
3.2 Principle of operation
The VEGATOR 132 is a double-channel signal conditioning instru-
ment for level detection with conductive sensors of series EL. Simple
monitoring and control functions can be realised via the integrated
relays.Typicalapplicationsaremonitoringfunctionssuchasoverll
and dry run protection as well as pump controls. An optional fail safe
relay is also available.
In conductive measurement, a low voltage is applied to two elec-
trodes. Alternatively, a single electrode can be used in metallic
vessels, the earth cable must then be connected to the vessel. By
using alternating voltage, electrolytic decomposition of the probe rods
and the medium is avoided. When the (conductive) medium comes
intocontactwiththeelectrode(s),acurrentowsandisdetectedand
further processed by the signal conditioning instrument.
Scope of delivery
Type label
Serial number
Application area
Functional principle

8
3 Product description
VEGATOR 132 •
46837-EN-170907
The switching point of the relay can be adjusted to the respective con-
ductivity by using the potentiometer.The output relay switches when
this current is reached (in dependence on the set mode).
Wide range power supply with a nominal voltage of 24 … 230 V AC,
50/60Hzor24…65VDC.
Detailed information about the power supply can be found in chapter
"Technical data".
3.3 Adjustment
All adjustment elements are located under a hinged front cover. The
operating mode, the switching delay and the Master/Slave switchover
can be set via a DIL switch block.The switching point can be adjusted
via a potentiometer.
3.4 Packaging, transport and storage
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.
The packaging of standard instruments consists of environment-
friendly, recyclable cardboard. For special versions, PE foam or PE
foil is also used. Dispose of the packaging material via 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 humidity 20 … 85 %
With an instrument weight of more than 18 kg (39.68 lbs) suitable and
approved equipment must be used for lifting and carrying.
Voltage supply
Packaging
Transport
Transport inspection
Storage
Storage and transport
temperature
Lifting and carrying

9
4 Mounting
VEGATOR 132 •
46837-EN-170907
4 Mounting
4.1 Mounting instructions
VEGATOR 132 is designed for carrier rail mounting (top hat rail
35 x 7.5 according to DIN EN 50022/60715). Due to its protection
rating of IP 20, the instrument is suitable for mounting in switching
cabinets.Itcanbemountedhorizontallyandvertically.
Note:
When several instruments are mounted together without space in
between, the ambient temperature at the installation location of the
instrument must not exceed 60 °C. Around the ventilation slots there
must be a distance of at least 2 cm to the next component.
The VEGATOR 132 in Ex version is an associated, intrinsically safe
instrumentandmustnotbeinstalledinhazardousareas.Safeopera-
tion is only ensured if the operating instructions and EU Type Approval
Certicateareobserved.VEGATOR132mustnotbeopened.A
certicationforExZone2isalsoavailableasanoption.
The instrument is suitable for standard ambient conditions acc. to
DIN/EN/IEC/ANSI/ISA/UL/CSA 61010-1.
Makesurethatthedegreeofcontaminationspeciedinchapter
"Technical data" meets the existing ambient conditions.
Ambient conditions

10
5 Connecting to power supply
VEGATOR 132 •
46837-EN-170907
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.
• Connect only in the complete absence of line voltage
• If overvoltage surges are expected, overvoltage arresters should
be installed
Note:
Install a separating facility for the instrument which is easy to access.
The separating facility 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.
The nominal range of the voltage supply can be 24 … 230 V AC,
50/60Hzor24…65VDC.
Detailed information about the power supply can be found in chapter
"Technical data".
The voltage supply of VEGATOR 132 is connected with standard
cable according to the national installation standards.
The sensors are connected with standard two-wire cable without
screen. If electromagnetic interference is expected which is above the
test values of EN 61326 for industrial areas, screened cable should
be used.
Make sure that the cable used has the required temperature resist-
anceandresafetyformax.occurringambienttemperature
Connect the cable screen on both ends to ground potential. In the
sensor, the screen must be connected directly to the internal ground
terminal.The ground terminal on the outside of the sensor housing
must be connected to the potential equalisation (low impedance).
If potential equalisation currents are expected, the connection on the
processing side must be made via a ceramic capacitor (e. g. 1 nF,
1500 V). The low-frequency potential equalisation currents are thus
suppressed,buttheprotectiveeectagainsthighfrequencyinterfer-
ence signals remains.
Take note of the corresponding installation regulations for Ex applica-
tions. In particular, make sure that no potential equalisation currents
owoverthecablescreen.Incaseofgroundingonbothsidesthis
can be achieved by the use of a capacitor or a separate potential
equalisation.
Safety instructions
Safety instructions
for Ex applications
Voltage supply
Connection cable
Cable screening and
grounding
Connection cable
for Ex applications

11
5 Connecting to power supply
VEGATOR 132 •
46837-EN-170907
5.2 Connection procedure
The pluggable terminals can be removed as needed to allow more
convenient connection.To make the electrical connection, proceed as
follows:
1. Mount the instrument as described in the previous chapter
2. Connect sensor cable 1 to terminal 1/2, and where applicable,
connect the screen
3. Connect sensor cable 2 to terminal 4/5, and where applicable,
connect the screen
4. When using several instruments on one sensor (Master/Slave
operation), connect terminal 3 of all instruments together
5. Connectswitched-opowersupplytoterminal16/17
6. Connect relay 1 to terminal 10/11/12
7. Connect relay 2 to terminal 13/14/15
Theelectricalconnectionisnished.

12
5 Connecting to power supply
VEGATOR 132 •
46837-EN-170907
5.3 Wiring plan
1
6
3
5
4
2
10 11 12
13 14 15
-+
16 17
EL MA/SL
123
EL
4 5
OPEN
13
2
123
Fig. 1: Wiring plan VEGATOR 132
1 Sensor circuit 1 (terminal 1 + 2) and Master/Slave connection (terminal 3),
max. level with two-point control
2 Sensor circuit 2 (terminal 4 + 5), min. level with two-point control
3 Relay output 1
4 Relay output 2
5 Voltage supply
6 Sensor
The terminals 1 and 4 are bridged internally. When using a single-rod
electrode, terminals 1 or 4 are connected to the metallic vessel and
terminals 2 and 5 to the respective electrode.When using double-
rod electrodes, terminals 1 or 4 are connected to the longer rod and
terminals 2 and 5 to the shorter one.
Information:
The connection terminals can be detached towards the front, if
necessary. This can be useful when working in tight spaces or when
exchanging an instrument.

13
5 Connecting to power supply
VEGATOR 132 •
46837-EN-170907
5.4 Wiring plan four-channel control
Two VEGATOR 132 are required for a four-channel control which must
beconguredviatheDILswitchtomaster/slavemode.
1
23
4
5
1
4
2
5
3
1
5
6 7
2
EL MA/SL
123
EL
4 5
OPEN
3
4
EL MA/SL
123
EL
4 5
OPEN
Fig. 2: Wiring plan VEGATOR 132
1 Sensor circuit 1 (terminal 1 + 2) and Master/Slave connection (terminal 3),
max. level with two-point control
2 Sensor circuit 2 (terminal 4 + 5), min. level with two-point control
3 Sensor circuit 3 (terminal 1 + 2) and Master/Slave connection (terminal 3),
max. level with two-point control
4 Sensor circuit 4 (terminal 4 + 5), min. level with two-point control
5 Sensor
6 VEGATOR 132 (master)
7 VEGATOR 132 (slave)

14
6 Setup
VEGATOR 132 •
46837-EN-170907
6 Setup
6.1 Adjustment system
1
2
3
4
Fig. 3: Display and adjustment elements
1 Potentiometer for switching point adjustment
2 DIL switch block
3 Signal lamps (LEDs)
4 Hinged front cover
6.2 Adjustment elements
Control lamps (LED) in the front plate indicate operation, switching
status and fault signal.
• Green
– Operating control lamp
– Mains voltage on, instrument is operating
• Red
– Fault indicator
– Fault on the sensor circuit due to sensor failure or line break
– The relay deenergises in case of failure
• Yellow
Control lamps

15
6 Setup
VEGATOR 132 •
46837-EN-170907
– Relay control lamp
– Lights with activated (current-carrying) relay status
The adjustment elements are located under a hinged front cover. To
open it, use a small screwdriver in conjunction with the slot on the
upper side of the front cover.To close it, push the cover at bottom and
toprmlyontothefrontcoveruntilyouhearthetworetainingclips
snap in.
The DIL switch block is located behind the front cover. The individual
switches are assigned as follows:
1
2
3
4
5
6
7
maxmin
MASL
0s
0s
0s
0s
8
9maxmin
+2s
+6s
t
+2s
+6s
t
Fig. 4: DIL switch VEGATOR 132
1 Mode, channel 1 (min./max. adjustment)
2 Linemonitoring,channel1O/On
3 Switch-on delay 2 seconds
4 Switch-on delay 6 seconds
5 Switch-odelay2seconds
6 Switch-odelay6seconds
7 Switchover Slave - Master
8 Two-pointcontrolOn/O
9 Mode, channel 2 (min./max. adjustment)
The requested operating mode is set with the min./max. switch (min.
detectioni.e.dryrunprotectionormax.detectioni.e.overllprotec-
tion)
• Dry run protection:Relayisswitchedowhenthelevelfalls
below the min. level (safe currentless state), relay is switched on
againwhenthemin.levelisexceeded(switch-onpoint>switch-o
point)
• Overowprotection:Relayisswitchedowhenthemax.levelis
exceeded (safe currentless state), relay is switched on again when
thelevelfallsbelowthemax.level(switch-onpoint<switch-o
point)
With these switches you can delay the changeover of the relays by
thesettime.Thiscanbeuseful,e.g.withuctuatingproductsurfaces,
forpreventingunwantedswitchingcommands.Theswitch-on/o
delays can be set independently of each other. If both switches, e.g.
Front cover
DIL switch block
Mode (min./max. adjust-
ment)
Switch-on/Switch-o
delay

16
6 Setup
VEGATOR 132 •
46837-EN-170907
of the switch-on delay, are activated, the times sum up. Delays of 2, 6
or 8 seconds can thus be adjusted.
The switching point can be adapted to the conductivity of the medium
via the potentiometer. Proceed as follows to adjust the switching
point:
• The electrode must be covered with at least 1 cm of medium
• Set the potentiometer to the left end position
• Check if the switching delay is set to 0
• Turn potentiometer slowly clockwise until the relay switches and
the yellow control lamp changes condition
• Turn the potentiometer a bit further so that the switching point is
always reliably reached
• Empty the vessel and check if the the relay switches again and the
yellow control lamp changes condition
Theinstrumentoerstheoptionofcontinuouslymonitoringthecable
totheelectrodeforlinebreak.Therequirementisthata220kΩresis-
tor be connected between the two electrodes or between electrode
andvessel.Adetectablelowcurrentthenowsevenwhentheelec-
trode is uncovered (i.e. not immersed). If the signal line is interrupted,
the red fault LED lights up.
Note:
The line monitoring is only carried out on channel 1. Channel 2 is not
monitoredandhenceno220kΩresistanceisrequired.Ifthereisa
faultsignalonchannel1,thiswillinuencebothoutputs,relay1and
relay 2 are then in safe state.
ForExapplications,the220kΩresistormustbeapprovedtogether
withthesensor.Forthispurpose,weoeranapprovedresistorspe-
ciallyadaptedtoVEGAinstruments.Youcanndfurtherinformationin
the documentation of the respective sensor.
Fig. 5: Ex resistor for line monitoring with sensors of the EL series
Note:
Linemonitoringmayonlybeactivatedifa220kΩresistoriscon-
nected between the two electrodes.
Switching point adjust-
ment, limit level
Line monitoring

17
6 Setup
VEGATOR 132 •
46837-EN-170907
The following functionalities can be selected via this switch:
• Single point control (double channel level detection with the same
switchon/switchopoint)
• Two-pointcontrol(leveldetectionwithdierentswitchon/switch
opoints)
As opposed to single point control, two-point control allows the
switch-onandswitch-opointstobesetatdierentlocations(hyster-
esis).Through the installation or the distance of the two electrodes,
thehysteresiscanbedenedindividually.Here,themax.levelmust
be set to sensor input 1, the min. level to sensor input 2.
Thetwo-pointcontrolisusedforexamplewhenllingandemptying
iscarriedoutviaapump.Thellingofavesselcanbeforexample
switchedonat10%andswitchedoagainat90%.Theoutputofthe
secondchannelbehavesidenticallyliketherstchannelprovidedthe
same mode is set. By changing the mode, the function of the relays
can be inverted.
If several instruments are to be connected to the same electrodes,
then all VEGATOR 132 must be connected together via terminal 3.
OneinstrumentmustbeconguredasMaster,allothersasSlave.
Throughsynchronizationofthemeasurementvoltages,faultyswitch-
ing due to crossover of measuring currents is avoided.
6.3 Proof test
Note:
Whenhandlingenvironmentallyhazardoussubstances,dangertothe
environment and to persons must be avoided. After setup, the proper
functioning of the instrument must be ensured by means of the proof
test described below.
• Detection of line break: Disconnect the sensor cable for the
duration of this test
– The red fault LED must light up
– Therelaymustbedeenergized
• Switchingpointmonitoring(overowprotection): Fill the ves-
sel up to the set switching point
– When the switching point is reached, the respective relay must
deenergize
• Switching point monitoring (dry run protection): Empty the
vessel down to the set switching point
– When the switching point is reached, the respective relay must
deenergize
6.4 Function table "Point level"
The following table provides an overview of the switching conditions
depending on the set mode and the level.
Two-point control
Master/Slave switchover

18
6 Setup
VEGATOR 132 •
46837-EN-170907
Sensor Signal conditioning instrument
Level Electrode LED yellow
(output)
LED red
(fault)
Relay
Uncovered ON
Covered OFF
any any OFF
Sensor Signal conditioning instrument
Level Electrode LED yellow
(output)
LED red
(fault)
Relay
Covered ON
Uncovered OFF
any any OFF
6.5 Function table, two-point control
The following charts provide an overview of the switching conditions
depending on the set mode and the level.
Sensor Signal conditioning instrument
Level Electrode LED yellow
(output)
LED red
(fault)
Relay
Uncovered
Uncovered
ON
Overllprotection,point
level (max.)
Dry run protection, point
level (min.)
Overllprotection,two-
point control

19
6 Setup
VEGATOR 132 •
46837-EN-170907
Sensor Signal conditioning instrument
Level Electrode LED yellow
(output)
LED red
(fault)
Relay
Uncovered
Covered
ON
Covered
Covered
OFF
Uncovered
Covered
OFF
Uncovered
Uncovered
ON
any any OFF
Sensor Signal conditioning instrument
Level Electrode LED yellow
(output)
LED red
(fault)
Relay
Uncovered
Uncovered
OFF
Uncovered
Covered
OFF
Covered
Covered
ON
Uncovered
Covered
ON
Uncovered
Uncovered
OFF
Dru run protection, two-
point control

20
6 Setup
VEGATOR 132 •
46837-EN-170907
Sensor Signal conditioning instrument
Level Electrode LED yellow
(output)
LED red
(fault)
Relay
any any OFF