CEMB S.p.A. - 23826 MANDELLO DEL LARIO (LC) I - Via Risorgimento 9
Tel. (+39)0341/706.111 - Telefax (+39)0341/706.299
www.cemb.com e-mail: stm@cemb.com
No contact transmitter TR-NC/8
Certified to Directive ATEX 94/9/CE
FUNCTION
The TR-NC/8 transmitter makes the following measurements:
- VB: Vibration (relative) of a rotor respect to its support
- AX: Displacement (axial) of a surface with respect to a fixed point, differential
displacement between two points.
- PH: Phase reference
The measurement is made by the correct positioning of a no contact sensor in the
vicinity of the point to be measured (made of ferrous material); the transmitter
supplies an output signal suitable for an acquisition system based on the two-wire
technique (current loop 4 to 20 mA).
The transmitter is certified for applications in areas classified as:
- Ex II 1 G Ex ia IIC T5
- Ex II 1 G Ex ia IIC T6
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PRINCIPLE OF OPERATION
The T-NC system generates a radio frequency field, which is radiated by the sensor
surface.
When the reference surface facing the sensor is impinged by such RF field, an eddy
current is generated on this surface. The energy required to generate this eddy current
(which is proportional to the distance between the reference surface and the surface of
the sensor), is reduced in proportion to that involved in the sensor; such difference
is measured by the transmitter.
The latter signal is amplified and processed by the transmitter which supplies an
output signal 4 to 20 mA with two-wire technique (current loop) proportional to the
measurement under examination.
TYPICAL APPLICATIONS
- Pick up of measurements over definite measurement ranges, directly interfaceable
with a remote indicator able to supply the power to the transmitter (+24 Vdc rated
voltage).
Plants where the presence of a DCS or a PLC allows centralized control of the
measurements found and relative alarm thresholds (if present).
The transmitter is also provided with a BNC-F socket which supplies a signal with a
scale factor of 200mV/mil (8mV/µm) in accordance with API670 standard. This signal can
be used for diagnostics of the machinery under control (e.g. by means of a spectrum
analyzer).
COMPOSITION
The measuring chain is made up as follows:
- a field-mounted no contact sensor series API670, provided with a cable which can be
integral with the sensor or unpluggable from it through an intermediate connector
- a transmitter TR-NC/8, connected in turn to the sensor cable via a coaxial connector
TECHNICAL CHARACTERISTICS OF EACH MEASURING CHAIN
Basic composition : sensor, extension cable, transmitter
Type of measurement : differential
Dynamic range : frequency 5 to 5000 Hz
amplitude max 2 mm (from 0.5 mm to 2.50 mm)
Linearity over the entire
range of measurement,
within the operating temperature limits indicated : ± 2%
Analog outputs : . 4 to 20mA–600 Ohm max. (current loop, 2-wire technique)
. BNC-F (scale factor 200mV/mil)
Power supply : +15 to +27Vdc; GND
Operating range : . temperature (sensor) = -35°C to +175°C
. temperature (transmitt.)= -20°C to +70°C (T5)
. temperature (transmitt.)= -20°C to +60°C (T6)
. humidity (sensor) = max 100%
. humidity (transmitter) = max 95% non condensing
. ambient (sensor) = IP67 EN 60529/10.91
. ambient (transmitter) = IP00 EN 60529/10.91
Connection : . miniaturized coaxial connector
(sensor / transmitter)
. screw terminal board model 476-CS/AL/4
(transmitter / user)
Weight of the transmitter : approx. 0.30 Kg
Weight of the sensor : approx. 0.10 Kg
Maintenance : None
Transmitter mounting : Connection for DIN rails: NS32-EN50035
NS35-EN50022
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Drawings : 56057 = Dimensions-mounting
38167 = Connections
Drawings to be
Required to CEMB : 53062/1÷6 = Types of sensor available
41670/1 = Types of extension available
54025/VB = Types of transmitter available for
Vibrations
54025/AX = Types of transmitter available for
Displacements
54025/PH = Types of transmitter available for
Phase
POSITIONING OF THE MEASURING CHAIN
Refer to dwg. 56057.
1) Make preparations on the machinery for mounting the sensor and any cable protection
devices (sheaths, ducts, etc.).
2) Separate (unless already disconnected) the extension cable and sensor parts from the
transmitter.
3) Mount the sensor with nominal air gap (Gap = 1.50 mm) on the device described in
point 1; GAP adjustment should be performed with the machinery in position K (ZERO
position with machine stationary) and is done by means of the thread of the sensor
and nuts (in standard kit) which act as nut/locknut (or else by means of a mounting
device provided with adjustment, e.g. supports Cemb series SR).
When mounting with two or more sensors, one alongside the other, it is necessary to
leave a minimum spacing of 25 mm in order to prevent mutual influence between the
signals.
4) Proceed to the electrical connection of the sensor to the transmitter and from the
latter to the measuring instrument as indicated in drawing 56057.
Min. supply voltage of the instrument should be 15 Vdc (+ 1 Vdc for every 50 ohm of
resistor inserted in the power supply loop), max. supply voltage should be 40 Vcc.
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TRANSMITTER SETTING
The TR-NC/8 instrument is normally supplied complete with the sensor already set.
Replacement of the sensors does not involve recalibration of the transmitter.
After arranging the sensor with the nominal air gap indicted above (1.50 mm) and
connecting it to the transmitter, proceed to adjust the setting of the sensor and
transmitter as follows:
- make the transmitter power connection on the terminals marked with POWER.
- connect a voltmeter across the transmitter terminals marked with GAP.
- make small movements of the sensor until reading a voltage of 5 Vdc on the voltmeter;
then lock the sensor in this position.
For VIBRATION measurements: in the absence of vibrations, current output is 4 mA ± 0.2
mA. It is possible to readjust the rest current by adjusting the trimmer marked by the
wording “4 mA” located at the bottom of the transmitter; it is advisable to perform
such operation after waiting for at least 15 minutes from switching on the transmitter.
For DISPLACEMENT measurements: in the “zero displacement” position (mid point of the
measurement range) output current is 12 mA ± 0.2 mA.
REMARKS REGARDING CORRECT POSITIONING OF TRANSMITTERS TR-NC/8
1) Never, under any circumstances, modify the sensor / transmitter cable length: this
would cause a measuring error.
2) The end part of the sensor must lie at a distance from metal materials different
from the one involved in measuring the distance: at least twice the max. amplitude
of measurement (see application drawing).
3) When mounting the sensor, a reference cone should be prepared at 90° vertex from
the sensor tip. No metallic material must be introduced in the cone apart from the
surface to be measured.
NOTES CONCERNING CERTIFICATION:
1) The use of ATEX certified transmitters is not allowed for different hazardous
conditions or for those exceeding the data specified on the nameplate affixed to
the transmitter.
2) The transmitter does not require maintenance. Any work regarding performance checks
or repair should only be carried out in a laboratory duly authorized by CEMB SpA.
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Ordering data
A B C D E F
TR-NC / 8 / / -- / / -- / /
A : Sensor thread
Code Thread
0 M10 x 1 standard
1 3/8”- 24UNF
2 Special to defined
3 M8x1
4 ¼”- 28UNF
N Not threaded
B : Sensore lenght (L)
Code Lenght mm
- not necessary data
C : Connection total lenght (sensor + cable + extension cable L1)
Code Lenght m
0 0.5 m
1 1.0 m
2 5.0 m
3 7.0 m
4 9.0 m
5 Special to defined
12 12.0 m
D : Extension cable lenght
E : Transmitter measuring range
E : Certified versions
Code Lenght
- not necessary data
Codice Campo di misura
0 100 µm-pp
1 125 µm-pp
2 200 µm-pp
3 250 µm-pp
4 Speciale da definire
5 ± 1 mm
6 ± 0,75 mm
7 ± 0,5 mm
8 1000 µm-pp
9 300 µm-pp
K Phase
Code Certificate type
0 Nothing
1T5 ATEX II 1 G Ex ia IIC T5
1T6 ATEX II 1 G Ex ia IIC T6
Example of an order
TR-NC/ 8 / 0 / - / 2 / - / 1 / 1
0 = Sensor thread M 10 - = not necessary data
- = not necessary data 1 = Measuring range 125 µm
2 = Connection total lenght = 5 m 1T5 = ATEX certification
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Certifications to ATEX 94/9/CE
0722 II 1 G Ex ia IIC T5
0722 II 1 G Ex ia IIC T6
CESI 03 ATEX 095
Legend of nameplate safety data
Marking of conformity with the applicable
European directives
0722
II
1
Number of the Notified Body carrying out the
surveillance (CESI)
Marking of conformity with Directive 94/9/EEC
and relative technical standards
Equipment suitable for surface applications
(not for mining)
Equipment intended for use in areas in which
explosive atmospheres caused by mixtures of
air and gases, vapours, mists or air/dust
mixtures, are present continuously,
frequently or for long periods, very high
level of protection.
Suitable for Zone 0
G Protection for Gases, Vapours, Mists
Ex ia
II C
T5
T6
CESI 03 ATEX
095
Ta = 70°C (T5)
Ta = 60°C (T6)
Equipment belonging to category "ia" with
instrinsic safety for Zone 0
Suitable for substances (gases) of group IIC,
also suitable for groups IIA and IIB
Temperature class T5 (surface temp.100°C)
Temperature class T6 (surface temp.85°C)
Certificate identification:
• Name of the laboratory issuing the CE-
type-examination certificate
• 03 = year of issuing the certificate
• 095 = number of the certificate
Ambient temperature -20 to +70 °C
Ambient temperature -20 to +60 °C
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ASTM18120
TR-NC-8-ATEX 03 GB
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