Endress+Hauser nivocompact FTC 731 User manual

nivocompact
FTC 731
Level Limit Switch
Installation and Operating Manual
BA 023F/00/en/03.92
015172-0001
Hauser + Endress
The Power of Know How

BA 023F/00/en/03.92
015172-0001
HD/CV4.2

Contents Page
Application 3
Application Examples 3
Technical Data 4
The Measuring System 6
Function 7
Installation 8
Project Planning 8
Examples for Mounting 9
Mounting 10
Type key 10
Connection 12
Wiring Connection 12
EC 30 (Two-Wire Connection) for AC 13
EC 32 (Three-Wire PNP) for DC 14
EC 33 (Three-Wire NPN) for DC 15
EC 34 (Relay Output) for DC and AC 16
Wiring On-Site 17
Calibration 18
Switching delay 18
Saftey switching 19
Particular Cases: Capacitance Calibration 20
Function Control 22
Maintenance 22
Troubleshooting 22
Replacement of Parts 24
Returning Parts for Repair 24
1

Nivocompact FTC 731
2

Application
The Nivocompact FTC 731 is used for limit detection in silos containing bulk
solids (for minimum or maximum indication).
It is also for use in the food processing industry.
It can be mounted in the silo from any direction.
Application Examples
Plastic granulates Grain Spices
Lime Kaolin Flour Semolina
Plaster Fodder
Cement
and similar bulk solids
Note:
Fine grained bulk solids should have dielectric constants εr≥1,6
Please contact us for advice if the dielectric constant of the bulk solid is not
known.
Fig. 1
Limit detection in bulk solid silos with the
capacitive level limit switch Nivocompact
FTC 731.
Application
3

Technical Data
Operating Data •Operating temperature in silo: –20 °C…+100 °C with dry bulk solids;
up to +60 °C with moist bulk solids
•Operating pressure pein silo: up to 6 bar
•Max. permissible load on probe: 4000 N lateral
•Grain size of material: up to approx. 10 mm
•Minimum relative dielectric constant εrof material: 2.0
(Factory-set, without calibration)
•Minimum adjustable dielectric constant εrof material: 1.6
•Ambient temperature for housing: –20 °C…+60 °C
•Storage temperature: –40 °C…+85 °C
Probe •Process connection: parallel thread G 11/2A acc. to DIN ISO 228/I
•Material of process connection: fibre-glass reinforced polyester (PBTP)
•Material of probe: fibre-glass reinforced polyester (PBTP)
•Insulation from material: fully insulated
Housing Versions •Aluminium housing, IP 55
•Aluminium housing, IP 66
•Aluminium housing with synthetic coating, IP 66
•Synthetic housing in PBTP, IP 66
(Protection IP…acc. to DIN 40050)
Cable Gland •Housing IP 55: standard PG in nickel-plated brass with NBR gasket
for cable diameter 7…10 mm.
•Housing IP 66: water-tight PG in polyamide with Neoprene-CR gasket
for cable diameter 5…12 mm.
Fig. 2
Dimensions Nivocompact FTC 731.
Nivocompact FTC 731 Technical Data
4

Electronic Inserts
•Terminal connections: for max. 2.5 mm2
•Measuring frequency: approx. 1.6 MHz
•Switching delay: approx. 0.5 s…approx. 20 s, selectable
•Minimum/maximum fail-safe switching: selectable with rotary switch
•Switching indication: red LED
•Power supply U∼: 21 V…250 V, 50/60 Hz
•Connected loads, short-term (max. 40 ms): max. 1.5 A;
max. 375 VA at 250 V;
max. 36 VA at 24 V
•Maximum voltage drop: 11 V
•Connected loads, continuous: max. 350 mA;
max. 87 VA at 250 V;
max. 8.4 VA at 24 V
•Minimum load current at 250 V: 10 mA (2.5 VA)
•Minimum load current at 24 V: 20 mA (0.5 VA)
•No-load current (eff.): < 5 mA
•Power supply U =: 10 V…55 V
•Superimposed AC voltage Upp: max. 5 V
•Current consumption: max. 15 mA
•Load connection: Open Collector; PNP (EC 32) or NPN (EC 33)
•Switching voltage: max. 55 V
•Connected load, short-term (max. 1 s): max. 1 A
•Connected load, continuous: max. 350 mA
•Residual current with transistor blocked: < 100 µA
•Protected against reverse polarity
•Power supply U =: 20 V…200 V
or
Power supply U∼: 21 V…250 V, 50/60 Hz
•Current consumption (eff.): max. 5 mA
•Peak inrush current: max. 200 mA, max. 5 ms
•Pulse current: max. 50 mA, max. 5 ms
•Pulse frequency: approx. 1.5 s
•Output: potential-free change-over contact
•Contact load capacity:
U∼max. 250 V, I∼max. 6 A,
P∼max. 1500 VA (cos ϕ= 1) or P∼max. 750 VA (cos ϕ ≥ 0.7)
U = max. 250 V, I = max. 6 A, P = max. 180 W
•Operating life: min. 105switchings at max. contact load
•Additional switching delay: max. 1.5 s
Type Key
See Page 10 for order specification key and order code.
Subject to modification
Electronic Insert EC 30
for AC (Two-wire Connection)
Electronic Inserts EC 32, EC 33
for DC (Three-wire Connection)
Electronic Insert EC 34
for DC and AC (Relay Output)
Technical Data
5

Accessories •Gasket for thread G 11/2A;
in elastomer/fibre (asbestos-free) supplied.
•Protective sun cover for aluminium housing
Material: polyamide
The Measuring System
The Nivocompact is an electronic switch.
The entire measuring system consists of:
•Nivocompact FTC 731
•power supply and
•connected control systems, switches, signal transmitters (e.g. process
control systems, PLC, relays, microcontactors, lamps, sirens etc.).
Fig. 3
Dimensions of protective sun cover
(accessory).
This cover prevents condensation in the
housing.
Fig. 4
The measuring system.
Nivocompact FTC 731 The Measuring System
6

Function
A metal sheet at the tip of the probe, within the insulation, and the
surroundings (e.g. silo walls) form the two electrodes of a capacitor, with a
high frequency voltage between them.
The limit value is based on the principle of a discharge circuit:
As long as the probe tip is in air with a dielectric constant of εr= 1, then the
discharge time constant is τ= R x CAwhere R is the resistance of the circuit
and CAthe capacitance of the capacitor formed by the probe tip and its
surroundings.
If bulk material with a dielectric constant εr≥2.0 moves into the electrical
high frequency field at the probe tip, then the capacitance CAincreases
and with it the time constant τ.
This change in the time constant is evaluated and causes the Nivocompact
FTC 731 to switch.
Fail-Safe Switching
The built-in feature for minimum/maximum fail-safe switching allows the
Nivocompact to be used in all applications requiring high operational safety:
Maximum Fail-Safe:
The current circuit is blocked if the probe is covered
or the power supply fails.
Minimum Fail-Safe:
The current circuit is blocked if the probe is uncovered
or the power supply fails.
A red LED on the electronic insert indicates switching status.
See also in Section »Safety Switching«, Page19
Fig. 5
Operation of the Nivocompact FTC 731 with
rod probe is not affected by material
build-up, even when several centimetres
thick, at the silo wall.
Function
7

Installation
Project Planning
Silo Material The Nivocompact FTC 731 can be installed in silos made of various
materials (e.g. metal, plastic, concrete).
Installation Point Note the angle of material flow or the outlet funnel when determining the
measuring point.
The Nivocompact switches (also with bulk solids with very small dielectric
constants) when the probe end is covered by a few centimetres of material
or when the material descends a few centimetres below the probe end.
The filling stream should not be directed onto the probe.
Installation in the Open When installing in the open, the protective sun cover as an accessory
protects the Nivocompact with the aluminium housing from excessive
temperatures and from condensation which may form in the housing due to
large temperature variations.
Correct Installation a) Protective sun cover for mounting in the open.
b) Heat insulation on the silo wall with high temperatures in the silo.
Incorrect Installation c) Incoming material can damage the probe.
The filling curtain can cause error switching.
Cable gland pointed upwards can allow moisture to enter.
Minimum Distances A minimum distance of 200 mm between the probe ends of two
Nivocompact FTC 731 instruments must be maintained to ensure
that there is no mutual interference.
The distance between the probe end of a Nivocompact FTC 731 and the
probe end a Nivocompact FTC 831 must be at least 500 mm.
To ensure that this distance is maintained when the rope probe of the
FTC 831 is swinging, a greater distance than this is recommended
especially with pneumatic systems.
The distance between the probe end of a Nivocompact FTC 731 and a
metal wall must be at least 120 mm.
Correct Installation Incorrect Installation
Fig. 6
General information for installing the
capacitive level limit switch Nivocompact
FTC 731.
Nivocompact FTC 731 Installation
8

Resistance to Load
Note the maximum lateral load of the probe rod when using it for minimum
detection.
Start-Up without Calibration
Start-up without calibration is possible if the requirements for installation are
met as shown in Fig. 7b). The material of the silo wall is not important.
Examples for Mounting
Correct Installation
a) The probe tip points slightly downwards so that material can slide off
more easily;
with short threaded socket (half socket length = 25 mm);
with minimum distance of 200 mm to the next Nivocompact FTC 731;
with minimum distance > 500 mm to a Nivocompact FTC 831.
b) Threaded socket + silo wall + material build-up is a maximum 50 mm
thick so that no calibration is required before start-up.
c) Minimum detection in the outlet cone is only possible with easy gliding,
free-flowing bulk materials.
Incorrect Installation
d) Probe end too near a wall (under the 120 mm distance)
e) Threaded socket too long with material build-up on the silo wall. *
f) In area where material is deposited in silo. *
g) Poor gliding characteristics of material causes material bridges. *
* In these cases it would be better to use a Nivocompact FTC 831 with
rope probe, installed from above.
Correct Installation Incorrect Installation
Fig. 7
Noting the information given for installation
will prevent errors occurring.
Installation
9

Mounting
•Open-end spanner 60 AF
•Screwdriver, blade width 5…6 mm or
Phillips screwdriver PZD 2
Preparation Compare the order code on the nameplate of your instrument with the order
specification key to ensure that the correct instrument is being installed.
The probe rod must not be shortened.
Screwing In
•Place the elastomer/fibre gasket supplied against the sealing surface of
the Nivocompact (Do not wind sealing material around the thread!).
•When screwing the Nivocompact into the threaded socket, turn the
instrument by the 60 AF hex nut only!
•If the instrument does not screw in easily, then only cut into the thread of
the threaded socket with care.
•A torque of 80 to 100 Nm is sufficient for a reliable seal up to 6 bar;
see Fig. 8.
A torque greater than 120 Nm destroys the plastic thread.
Tools Required for Installation
FTC 731 capacitive level limit switch with rod probe
Threaded boss with rod probe
Housing
A Aluminium housing, IP 55
B Aluminium housing, IP 66
R Aluminium housing, coated, IP 66
K PBTP synthetic housing, IP 66
Y Check special version
Electronic Insert (mounted in housing)
1 21 V…250 V, 50/60 Hz (EC 30)
Two-wire AC connection
2 PNP 10 V…55 V= (EC 32)
Three-wire DC connection
3 NPN 10 V…55 V= (EC 33)
Three-wire DC connection
4 Relay, 21…250 V AC/200 V= (EC 34)
AC or DC connection
with relay output (change-over contact)
9 Check special version
Order code on nameplate
FTC 731
Fig. 8
A torque of approx. 80 Nm when screwing in
means that:
If you weigh approx. 80 kg, you can support
your total body weight holding the spanner
(60 AF) approx. 10 cm from the centre of
rotation.
Nivocompact FTC 731 Installation
10

Rotating the Housing
The housing can be rotated if the cable gland is facing in the wrong
direction after the Nivocompact has been securely screwed in:
Loosening
•Unscrew and remove the housing cover
•Loosen the central screw in the electronic insert
•Remove the plug-in electronic insert from the housing using the handle
•Slightly loosen the 3 screws in the housing, see Fig. 9.
Rotating
•The housing can now be rotated through 360°.
When mounting an FTC 731 laterally, the cable gland should point
downwards so that no moisture can enter
Tightening
•Tighten up the 3 screws in the housing so that the housing is well sealed
at the hex nut
•Insert the electronic insert in the plug
•Securely tighten the central mounting screw
while making sure that the cable gland remains free
Fig. 9
Loosening and rotating the housing.
Fig. 10
Tightening the electronic insert.
Installation
11

Connection
Wiring Connection
Main Features of the Different
Electronic Inserts The last number of the order code on the nameplate identifies which type of
electronic insert is mounted in the Nivocompact FTC 731:
1=Electronic insert EC 30
Two-wire AC: 21 V…250 V
Electronic switch, max. 350 mA
2=Electronic insert EC 32
Three-wire DC: 10 V…55 V
Transistor circuit, load connection PNP, max. 350 mA
3=Electronic insert EC 33
Three-wire DC: 10 V…55 V 10 V…55 V
Transistor circuit, load connection NPN, max. 350 mA
4=Electronic insert EC 34
with potential-free relay output
AC power supply 21 V…250 V or
DC power supply 20 V…200 V
Load Limit Values Note the limit values of the loads to which you want to connect the
Nivocompact. Exceeding the load can destroy the electronic insert (or the
relay contact in the EC 34)
Fuse Ensure that the rating of the fine-wire fuse corresponds to the maximum
load to be connected.
The fine-wire fuse does not protect the electronic insert of the Nivocompact
FTC 731.
Diameter of Wiring Because of the small current used, only small diameter cabling is required.
Low-cost cabling with diameter of 0.5 mm2to max. 1.5 mm2is
recommended.
Earth Connection, Grounding The Nivocompact must be grounded to give reliable operation free from
interference. This is done by either connecting it to a grounded silo with
metal or reinforced concrete walls or else to the earth conductor PE.
The probe requires a good counter potential. This is done by connecting
the ground connection on the outside of the housing to an electrically
conductive part of the silo. If the silo is made of a non-conductive material,
then connect to the ground connection conductive and grounded parts
near to the silo. The connecting cable must be as short as possible.
Fig. 11
Electrical connections available with the
different electronic inserts.
Nivocompact FTC 731 Connection
12

Connecting the Nivocompact with Electronic Insert EC 30
for AC (Two-Wire Connection)
Connecting in Series to a Load
The level limit switch Nivocompact with electronic insert EC 30 must
- like all switches - be connected in series with the load (e.g. relays,
microcontactors, lamps) to the power supply.
Direct connection to the power supply without any intermediate load
connected (short-circuit!) will result in immediate and permanent damage
to the electronic insert.
The load can be connected to Terminal 1 or 2 of the electronic insert.
It is unimportant whether L1 is connected to Terminal 1 or 2.
Power Voltage
The voltage across Terminal 1 and 2 of the electronic insert must be at least
21 V.
The power voltage must be correspondingly higher to compensate for the
voltage drop across the connected load.
Load Cutoff
Note that loads connected in series are not completely disconnected from
the power supply if the electronic switch in the electronic insert of the
Nivocompact »disconnects« (blocks) with level alarm.
Because of the current requirements of the electronics, a small »no-load«
current still flows through the connected load.
When the load is a relay with a very small retaining current, then the relay
may not de-energise. In this case connect an additional load in parallel to
the relay, e.g. a resistor or signal lamp.
Fig. 12
Connecting the Nivocompact FTC 731
with electronic insert EC 30
U1-2∼:21 V...250 V across Terminals 1 and 2
of the EC 30
R: Connected (external) load, e.g. relay
F: Fine-wire fuse, load-dependent
UR: Voltage drop across the load and the
fine-wire fuse
M: Ground connection to silo or to metal parts
near to the silo
E: Grounding
Connection
13

Connecting the Nivocompact with Electronic Insert EC 32
(Three-Wire PNP) for DC
Transistor Circuit for Load The load connected to Terminal 3 is switched by a transistor, contactless
and therefore without bouncing.
Terminal 3 has a positive signal in normal switching mode.
The transistor is blocked on level alarm or with a power failure.
Protection Against Voltage Peaks Connecting to an instrument with a high inductance:
a voltage limiter should be connected.
Fig. 13
Connecting the Nivocompact with electronic
insert EC 32 (PNP)
F: Fine-wire fuse, load-dependent
R: Connected load, e.g. PLC, PCS, relay
M: Ground connection to silo or metal parts
near to the silo
E: Grounding
Nivocompact FTC 731 Connection
14

Connecting the Nivocompact with Electronic Insert EC 33
(Three-Wire NPN) for DC
Transistor Circuit for Load
The load connected to Terminal 3 is switched by a transistor, contactless
and therefore without bouncing.
Terminal 3 has a negative signal in normal switching mode.
The transistor is blocked on level alarm or with a power failure.
Protection Against Voltage Peaks
Connecting to an instrument with a high inductance:
a voltage limiter should be connected.
Fig. 14
Connecting the Nivocompact with electronic
insert EC 33 (NPN)
F: Fine-wire fuse, load-dependent
R: Connected load, e.g. PLC, PCS, relay
M: Ground connection to silo or metal parts
near to the silo
E: Grounding
Connection
15

Connecting the Nivocompact with Electronic Insert EC 34
(Relay Output) for DC and AC
Power Supply With AC, it is unimportant whether L1 or N is connected to Terminal 1.
With DC, it is unimportant whether L+ or L– is connected to Terminal 1.
Relay Contact for Load The load is connected over a potential-free relay contact (change-over
contact).
The relay contact breaks the connection between Terminal 3 and Terminal 4
on level alarm or with a power failure.
Protection Against Voltage Peaks
and Short-Circuiting Protect the relay contact by connecting a spark barrier to instruments with
high inductance.
A fine-wire fuse (load-dependent) can protect the relay contact
if a short-circuit occurs.
Fig. 15
Connecting the Nivocompact with electronic
insert EC 34 (relay output)
F1: Fine-wire fuse 200 mA, semi-time lag
recommended
F2: Fine-wire fuse to protect the relay
contact, load-dependent
M: Ground connection to silo or to metal parts
near to the silo
E: Grounding
Nivocompact FTC 731 Connection
16

Wiring On-Site
•Open-end spanner 22 AF
•Screwdrivers, blade width approx. 4 mm and 7 mm or
Phillips screwdrivers PZD 1 and PZD 2
•Usual electrical tools
Before connecting, make sure that the power supply used is the same as
that stated on the nameplate of the electronic insert.
Electrical Connection
Connect the Nivocompact according to the appropriate diagram Fig. 12 to
Fig. 15.
Ensure that no water gets into the housing while connecting up.
The gasket in the standard cable gland is designed for cable diameters
from 7 mm to 10 mm.
A suitable gasket must also be used for other cable diameters.
You can seal with the »water-tight« cable gland with cables having
diameters from 5 mm to 12 mm.
Ensure that there is a good, short ground connection from the housing of
the Nivocompact to the silo or to grounded metal parts near to the silo.
After Connecting
Screw the thread of the cable gland securely to comply with the standards
of Protection IP 55 or IP 66.
For applications in the open or in moist surroundings, sealing the standard
cable gland with sealing compound is also recommended.
(This is not required with the »water-tight« cable gland).
Tools Required for Installation
Fig. 16
Note the power voltage stated on the
nameplate!
Connection
17

Calibration
•Screwdriver with blade width approx. 3 mm
•Screwdriver with blade width approx. 4 mm
The rotary switches and adjusting elements for calibration are on the
electronic insert in the housing.
Directly beside these calibration elements are the power connections with
voltages up to 250 V.
Only use a screwdriver which has insulation as far as the blade or else tape
over the terminals with insulating tape before calibration.
Turn on the power supply.
Switching Delay Switching delay can be adjusted between approx. 0.5 s and 20 s.
See Fig. 17. It is the same time interval for the sensor whether free
or covered.
Select the optimum time for your application.
Accurate adjustment with a free probe is possible:
•Touch the central screw in the electronic insert with the screwdriver.
After a preset time, the Nivocompact switches, the LED goes off
or comes on.
•Keep altering the adjustment until the exact switching delay is set.
Tools Required for Calibration
Fig. 17
Setting the switching delay.
Nivocompact FTC 731 Calibration
18