Endress+Hauser gammapilot FTG 671 Technical Information

Technical
Information
TI 177F/00/en

Radiometric Level Measurement

gammapilot FTG 671

Non-invasive, radiometric limit detection
Intrinsically safe signal circuit [EEx ib] IIC /
ATEX II (2) GD
For scintillation or Geiger-Müller detector

Application

The Gammapilot FTG 671 transmitter is
designed for

•

non-invasive, level limit detection

in containers - mixers, reactors,
hoppers, silos, tanks - with inflammable,
abrasive, poisonous and aggressive
bulk material and liquids, e.g. in acid
tanks, boilers, cement silos, ballast
hoppers, cyclones, cupolas, rotary
furnaces etc.. Thanks to the fact that the
measuring system is fitted externally, it
also finds application in the food
processing industry.

Gammapilot transmitters may also be
used for applications in explosion
hazardous areas, and possess
intrinsically-safe sensor circuits
conforming to EEx ib IIC, or EEx d IIC,
EEx de IIC depending on the detector.

The Gammapilot
FTG 671 transmitter is a
19" plug-in card, shown
here in Monorack II
housing

Features and Benefits

• Suitable for scintillation detector

DG 57 or Geiger-Müller counters
DG 17 or DG 27

• Uses lowest possible source activity

with DG 57/100 mm or longer

•

Digital signal transmission

- Interference-free function with
two-core installation cable up to
1000 m

•

Intrinsically safe sensor circuits

- Ex-protection withoutZener barriers

approved as overspill protection
(VBF, WHG Germany) and for use
in explosion hazardous areas

•

Simple operation with parameter
matrix

- Uniform handling as for all
Commutec transmitters

•

Practical background functions

- Automatic compensation of source
decay

- Automatic adjustment of switch
point

•

Commutec transmitter

- Simple connection to automatic
systems via Rackbus

- Up- and download of data

The Power of Know How

Hauser+Endress

Measuring System

Gammapilot
FTG 671
transmitter

Standard level detection
application showing the
arrangement of the
system components
source container,
detector and transmitter

Source

Measuring System

A working system for level limit detection
comprises:

Gammapilot FTG 671 transmitter,

•

• QG 020 or QG 100 source container

with Co 60 or Cs137 gamma source

• DG 17, DG 27 Geiger-Müller counter

or DG 57 scintillation counter.

Detector

Min./max.
relays

Signal Input Circuit

The Gammapilot supplies the power to
the DG… detector and, depending on
type, the detector returns an
interference-free pulse frequency or
pulse code modulated countrate signal.
The intrinsically safe signal input is
electrically isolated from the transmitter
supply and the outputs.

Conveying limestone
Gamma radiation
barriers control the
drying process

Automatic filling of beer
barrels
The level is checked as
the barrels move past
the barrier

Scintillation Counter DG 57

Most measurement systems use the DG
57 scintillation counter, thus ensuring:

• highest sensitivity

•

with lowest source strength.

Endress+Hauser have many years of
experience with rod scintillation counters
and the new DG 57/100 mm counter has
been specially developed for limit
detection. Sensitivity can be further
increased by using the DG 57/
400 mm or longer.

Minimum
level
detection

Vibration
channel

Maximum
level
detection

FTG 671

Output Signals

The Gammapilot FTG 671 has two limit
relays which can be operated with freely
adjustable hysteresis independently of
each other in minimum or maximum
fail-safe mode.

Self-Monitoring Function

The Gammapilot FTG 671 continuously
monitors all signal lines. On fault
condition:

•

An alarm relay with potential-free
changeover contact de-energises

•

In default condition the limit relays also
de-energise.

FTG 671

Feed rate 1
barrel/2s

Filling
station

Full move
forward
Half full are
rejected

2

Measurement Principle

Principle limit detection
by gamma radiography

Nmax

Countrate

Nmin

Change in countrate
as product moves
through barrier

1000

Statistical fluctuation
in countrate

Countrate due to residual
and background
radiation

time

Gamma-Ray Absorption

Radiometric level measurement relies on
the fact that gamma rays are absorbed
as they penetrate a material. The
attenuation of the radiation is dependent
upon the density ρ, the thickness d of
the material as well as the linear
absorption factor µ. This in turn is
dependent on the material and gamma
source. The attenuation is calculated
from the formula

µ . ρ . d

= e

F

s

The radiation also decreases with the
square of the distance between source
and detector.

Limit Detection

For limit detection µ, and d are
constants and the detected radiation
level depends upon the presence or not
of the penetrated material:

•

The countrate is at a maximum when
the path to the detector is completely
free and

•

at a minimum when all the radiation
has to travel through the material and
is attenuated.

Radiation Statistics

The emission of gamma rays by a
radioactive source is governed by the
laws of statistics. For this reason the
measurement precision of gamma
systems is dependent on the statistical
variation in countrate. The variance, i.e.
the degree of variation between
measurements, depends upon the time
interval chosen. The precision of the
measurement depends on the chosen
confidence level - 1σ, 2σ or 3σ. For a
countrate of N pulses per second:

•

σ =N;±

68.28 % confidence

level

•

2= 2N;σ±

•

3= 3N;σ±

95.48 % confidence level

99.74 % confidence level

Normally, a confidence level of 2σ is
used. The statistical variation can be
reduced by increasing the sampling or
integration time τ:

Statistical variation

2N±

=

τ

For limit switching the integration time
corresponds to the response time of the
relay.

The maximum and minimum countrates

and N

N

max

are obtained when the

min

transmitter is calibrated, whereby their
dependency is given by:

max

−µ . ρ . d

e

= N

N

min

The switch points can be set anywhere
within these two countrates, which are
normalised to produce the end values 0
and 100.

3

Background Functions

The Gammapilot FTG 671 is equipped
with a number of background functions
which ensure accurate and reliable limit
switching. Thus, for example, the
statistical fluctuations in countrate and
decay of the gamma source described
above are accounted for without any
action on the part of the operator.

After calibration, the FTG automatically
sets the switch points to preset values. It
warns the operator if incorrect limits are
entered, and when the activity of the
source is no longer sufficient for reliable
switching.

Operation

Measured value display showing
normalised countrate at V0H0

Matrix selection keys

Parameter entry keys

Matrix position indicator

Limit relay LEDs

• Red lit, relay de-energised

• Green lit, relay energised

Front panel of
Gammapilot FTG 671
showing configuration
and display elements

Green communications LED

• Lights when communicating

Alarm relay LED

• Lights on fault condition,
alarm relay de-energises

• Flashes on warning,
alarm relay remains energised

Configuration at Front Panel

Gammapilot FTG 671 transmitters can
be configured at the front panel.

Six keys access a parameter matrix,

•

defined by a vertical (V) and horizontal
(H) position, in which relevant data can
be entered

• The selected matrix field and

parameter are indicated in the
LC-display

• A display of normalised countrate,

0-100, is available during operation

Remote Configuration

The transmitter can also be configured
by a Commulog handheld terminal or via
the Rackbus.

•

The Commulog is plugged into the
front panel

•

The data exchanged are displayed
with supplementary information in
plain language on the large
LC-display.

When the Commulog is unplugged,
Racksyst operation mode is selected
automatically.

Communication sockets for
Commulog VU 260 Z

Operational Status

The operational status of the transmitter
is indicated by means of six LEDs which
can be clearly seen from a distance.

• The green and red LEDs in the central

field indicate the limit relay status:
red de-energised, green energised

• The green LED below lights when the

Gammapilot is communicating with the
Commulog VU 260 Z handheld
terminal or the ZA 67… computer
gateway

• The red LED in the diagnostics field

flashes to indicate a warning or lights
on fault condition.

Diagnosis

The following possibilities exist for
on-line diagnosis:

•

an error code can be read from the
matrix position V9H0: the associated
text can be read with the Commulog
VU 260 Z.

•

the transmitter can be connected to a
personal computer via commissioning
and service software, e.g.,
Commutool.

The Commulog VU 260 Z
provides instant access to
measured data

4

Remote Control

The Gammapilot
FTG 671 communicates
with a supervisory
controller via the
two-core Rackbus and a
ZA 67… computer
gateway
Three possibilities exist:
Modbus, Profibus or FIP.

Rackbus

Sensors

Personal Computer
or other controller or configurator

e.g.
PROFIBUS

PROFIBUS-compatible
programmable logic
controller

e.g.
ZA 673

Actuators

Process Control Systems

Gammapilot FTG 671 transmitters are
easily integrated into supervisory control
systems.

• Parameters are addressed over the

Rackbus by the ZA 67… gateway
which presents them in appropriate
format to the connected network

• Up to 64 Commutec transmitters (max.

128 measuring points) can be
individually controlled and operated
on-line from the control room. Each is
accessed via a unique address

• Gateways and operating programs are

available for a variety of fieldbuses,
programmable logic controllers (PLC),
process control systems (PCS) and
personal computers (PC).

The resulting dialogue between
supervisory controller and subordinate
transmitters makes for a safer and more
flexible plant organisation.

Commutec operating
programs provide an
overview of process
variables for small and
medium-sized plants

5

Installation

Mounting

Racksyst plug-in cards must be installed
outside explosive hazardous areas in a
rack or protective housing.
Endress+Hauser can provide the
following alternatives:

19" rack (84 HP wide) for mounting up

•

to 12 transmitters in the control room
Half 19" wide field housing with

•

Protection IP 65 for five 7 HP
transmitters and a power supply unit
Monorack II housing (7 HP) for single

•

or multiple mounting on a local control

panel.
For EMC reasons we advise you to use
special guide rails with metal clips when
the plug-in card is installed in the field
housing or subrack. This connents the
instrument input filter to the subrack
potential.

Field housing

Detector Connection

Use two-core installation cable,

•

max. resistance 25 Ω per core
Use shielded cable: ground at the

•

detector end if electromagnetic
interference is to be expected.
Note local regulations when laying

•

cable in hazardous areas.

Non Ex-area

Monorack II housing

PCM

Inputs or

PFM

Rackbus

Connection of Instrumentation

The circuit zero of the Gammapilot is
connected to the negative terminal of
the 24 V supply. One of two electrically
isolated signal inputs can be used:

• Inputs d2 and d4 are for PCM signals

from DG 57 scintillation counters

• Inputs z2 and z4 are for PFM signals

from Geiger-Müller counters DG 17
resp. DG 27.

Ex-area

Non Ex-area

Remote dialog

Connection diagram for
Gammapilot FTG 671

Relay 1

Relay 2

Alarm relay

Power supply

6

Relay 1

Relay 2

Alarm relay

DC supply

Technical Data

Dimensions in mm of
plug-in card
1" = 25.4 mm

Environment

Operating temperature: 0 °C...+70 °C

•

Storage temperature: -20 °C...+85 °C

•

Climatic class to DIN 40 040: KSE

•

Electromagnetic compatibility (EMC):

•

Emitted interference to EN 61326;
Class A equipment;
Immunity to interference to EN 61326;
Annex A (industry sector) and
NAMUR EMC Recommendation
(NE 21)

Construction

Design: 19", 7 HP, Racksyst II* plug-in

•

card to DIN 41 594 (Europa card)

• Front panel: black synthetic with blue

field inlay, grip and markings

• Ingress protection (DIN 40 050):

Front panel IP 20
Card IP 00

• Dimensions: see diagram

• Weight: approx. 0.3 kg

• Multipoint plug: conforming to

DIN 41612, Part 3, Type F (25-pole)
Coding pins in positions 2 and 7

Type II Racksyst cards cannot be installed

*

in Type I Monorack housings

Electrical Connection

Power supply: 24 V DC (+6 V…-4 V);

•

- residual ripple 2 V, within tolerance
Supply current: max. 135 mA

•

Power consumption:

•

max. 3.3 W at 24 V, max. 4.0 W at 30 V
Signal inputs:

•

Electrically isolated from the rest of the
circuitry.

- Protection EEx ib IIC, EEx d IIC or
EEx de IIC for DG 57.
Non-Ex for DG17/27.

Relay Outputs

Two independent limit relays each with

•

a potential-free change-over contact
Freely selectable switchpoint and

•

hysteresis
Fail-safe mode: maximum or minimum

•

selectable
Third alarm relay with potential-free

•

change-over contact for fault
indication

Max. switching capacity:

•

- 2.5 A, 250 VAC,

- 300 VA (cos ϕ= 0.7),

- 600 VA (cos ϕ= 1)

- or 100 VDC, 100 W

Detectors

• DG 57 rod scintillation counter

• DG 17, DG 27 Geiger-Müller counters

Certificates

•

Explosion protection: [EEx ib] IIC /
ATEX II (2) GD
PTB No. Ex-93.C.2145 X

•

Explosion protection: EEx d ib IIC,
EEx d IIC and EEx de IIC,
dependent upon detector DG 57
PTB No. Ex-85/2051

•

Overspill protection (Germany)

7

Product Structure

Gammapilot FTG 671

Certificate

F [EEx ib] IIC*/ATEX II (2) G

Approval for use as overspill protection (Germany)

Version

A Single measurement point

Supplementary
Documentation

FTG 671-

product designation

EEx d ib IIC, EEx de IIC, EEx d IIC are determined by the DG 57 detector
Non-Ex for DG 17/27

Radiometric measurement

❑

Applications in all industries
Practical know-how PK 001F/00/en

Gammapilot, Gammasilometer

❑

System Information SI 014F/00/en
Gammapilot FTG 671

❑

Operating instructions BA
082F/00/en

Racksyst planning hints for rack-

❑

mounting or Racksyst field housings
and self-adhesive connection
schematics

Monorack II System Housing

❑

Technical Information TI 183F/00/en

❑

QG 020/100 Source Containers

Gamma radiation source

❑

Technical information TI 213F/00/en
Commulog VU 260 Z Handheld

❑

Terminal
Technical Information TI 140/00/en

ZA 672 Modbus Gateway

❑

Technical Information TI 148/00/en
ZA 673 PROFIBUS Gateway

❑

Technical Information TI 162F/00/en
ZA 674 FIP Gateway

❑

Technical Information TI 167F/00/en
Commutec Operating Program

❑

Technical Information TI 113/00/en

Technical Information TI 264F/00/en

❑

QG 2000 Source Container
Technical Information TI 346F/00/en

❑

DG 57 Scintillation Counters
Technical Information TI 180F/00/en

05.02/PT1

TI 177F/00/en/06.03
SL/CV8.0

Endress

The Power of Know How

+

Endress+Hauser
GmbH+Co. KG
Instruments
International
P.O. Box 2222
D-79574 Weil am Rhein
Germany

Tel. [phone]
Fax [phone]
http://www.endress.com
[e-mail]

Hauser