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