Endress+Hauser promag 31 User manual

promag 31
Electromagnetic
Flow Measuring System
BA 028D/06/e/02.97
No. 50084257
valid from software version
V3.01.XX (measuring amplifier)
Cold Water Fiscal Metering
Operating Manual

Safety Instructions
Correct Usage
•The Promag 31 is only to be used for measuring the flow of conductive fluids.
•The Promag 31 flowmeter is designed and checked according to the regulations in
force EN 61010 “Protection Measures for Electronic Measuring Equipment”). The
flowmeter may be dangerous if it is not used for the purpose it was designed for or
is used incorrectly.
Please carefully note the information provided in this
Operating Manual indicated by the pictograms:
•The manufacturer assumes no liability for damage caused by incorrect use of the
instrument. Modifications and changes to the instrument may not be carried out.
Personnel for Installation, Start-up and Operation
•Mounting, electrical installation, start-up and maintenance of the instrument may
only be carried out by trained personnel authorized by the operator of the facility.
Personnel must absolutely and without fail read and understand this Operating
Manual before carrying out its instructions.
•The instrument may only be operated by personnel who are authorized and trained
by the operator of the facility. All instructions in this Manual are to be observed
without fail.
•With special fluids incl. those used for cleaning, E+H will be pleased to supply
information concerning the chemical resistance properties of wetted parts.
•The installer has to make sure that the measuring system is correctly wired
according to the wiring diagrams. The measuring system is to be grounded.
•Please observe all provisions valid for your country and pertaining to the opening
and repairing of electrical devices.
Repairs, Dangerous Chemicals
The following procedures must be carried out before a Promag 31 flowmeter is sent to
Endress+Hauser for repair:
•A note must always be enclosed with the instrument, containing a description of
the fault, the application, and the chemical and physical properties of the product
being measured.
•Remove all residue which may be present. Pay special attention to the gasket
grooves and crevices where fluid may be present. This is especially important if the
fluid is dangerous to health, e.g. corrosive, poisonous, carcinogenic, radioactive,
etc.
•No instrument should be returned to us without all dangerous material being
removed first, e.g. in scratches or diffused through plastic.
Incomplete cleaning fo the instrument may result in waste disposal or cause harm to
personnel (burns, etc.). Any costs arising from this will be charged to the owner of the
instrument.
Technical Improvements
The manufacturer reserves the right to modify technical data without prior notice.
Your local E+H Sales Office will supply you with all current information and any
updates to this Operating Manual.
Warning!
Safety Instructions Promag 31
2 Endress+Hauser

ContentsContents
Safety Instructions . . . . . . . . . 2
1. System Description . . . . . . . 5
1.1 Fields of application . . . . . . . . . 5
1.2 Principle of measurement . . . . . . . 5
1.3 The Promag 31 measuring system . . . 6
1.4 Design of the measuring system . . . . 8
2. Mounting and Installation . . . 11
2.1 General Information . . . . . . . . 11
2.2 Transport instructions for Promag
from DN 350 / 14" . . . . . . . . . 12
2.3 Mounting Instructions . . . . . . . 13
2.4 Mounting Promag 31 F . . . . . . . 16
2.5 Turning the transmitter housing
and local display
(compact version) . . . . . . . . . 18
2.6 Mounting the transmitter
(remote-mounted version) . . . . . . 19
2.7 Potential equalisation . . . . . . . 20
2.8 Earthing in an area with severe
interference . . . . . . . . . . . 21
3. Electrical Connection . . . . . 23
3.1 General information . . . . . . . . 23
3.2 Connection to the transmitter . . . . 23
3.3 Connection of the remote version . . . 24
3.4 Wiring diagrams . . . . . . . . . 25
3.5 Cable specifications . . . . . . . . 27
4. Operation and Commissioning . 29
4.1 Instrument Functions . . . . . . . . 29
4.2 Setting unit parameters with miniature
switches . . . . . . . . . . . . 33
4.3 Local display . . . . . . . . . . . 36
4.4 Commissioning . . . . . . . . . . 38
5. Fault Location and Remedies . . 39
5.1 Behaviour of the measuring equipment
in the event of a fault or alarm . . . . . 39
5.2 Instructions for fault location and remedies 40
5.3 Replacing the transmitter electronics . . 41
5.4 Repairs . . . . . . . . . . . . . . 43
6. Technical Data . . . . . . . . 45
6.1 Dimensions and weights . . . . . . . 45
6.2 Technical data: Sensor . . . . . . . . 48
6.3 Technical data: Transmitter and
measuring system . . . . . . . . . 52
6.4 Nominal diameter and flow rate . . . . 53
6.5 Conceptual definitions . . . . . . . . 54
6.6 Error limits . . . . . . . . . . . . 55
Index . . . . . . . . . . . . . 57
Documentation for Ex instruments
Instruments which are used in the explosion hazardous area are supplied with a
separate “Ex documentation”, which is an integral part of this Operating Manual.
The instructions and connected loads provided in this supplement must absolutely
be observed.
An appropriate icon is shown on the front of this document according to the
approval given and the test centre.
Promag 31 Contents
Endress+Hauser 3

Promag 31
4 Endress+Hauser

1. System Description
1.1 Fields of application
The measuring system Promag 31 possesses the PTB licence for the transport of cold
water (waste water) and at an attractive price offers accurate magnetic-inductive flow
measurement of fresh water with a minimum conductivity of 5 µS/cm. The measuring
system operates within a temperature range of 0 to 30 degrees celsius and can be
deployed for the following uses in the supply of drinking water:
Local water network Internal monitoring of delivery pipe network
Junctions Calculation of the bill from the main supply pipe
Tank inlet points
(incl. pump stations) Monitoring of the water source. For example, the amount of ground water.
Tank outlet points Certification for the amount supplied to the
delivery network
Overland supply pipe of a water
network Monitoring of the withdrawal and supply of different water works in a supply pipe
1.2 Principle of measurement
In accordance with Faraday’s law of induction, a voltage is induced in a conductor
that is moved through a magnetic field. In the magneto-inductive principle of
measurement the flowing medium represents the moving conductor. The induced
voltage is proportional to the flow velocity and is fed to the measuring amplifier by a
pair of electrodes. Across the cross-section of the pipe the flow volume is calculated.
The DC magnetic field is generated by a switched direct current of alternating
polarity. Together with the patented “Integrated Autozero Circuit” this assures a stable
zero point and makes the measurement independent of the medium and insensitive to
entrained solid particles. In our works every unit is calibrated on modern calibrating fa-
cilities, referable to international standards. There is no need for it to be adapted to
suit changing media.
ba028y01
Ue=B
⋅L ⋅v
Q=v
⋅A
Ue= induced voltage
B = magnetic induction
L = distance between electrodes
v = flow velocity
Q = volume flow
A = pipe cross-section
Fig. 1
Promag 31 1. System Description
Endress+Hauser 5

1.3 The Promag 31 measuring system
The promag measuring system is a fully modular, both mechanically and electrically.
The equipment can be extended by exchanging electronic boards. Thus the measur-
ing point can be optimally equipped and updated. The illustration below gives an
overview of the complete Promag 31 system.
Caution!
The Promag 31 is available with different Ex-certificates. Information about the current
status can be found from your existing E+H representive.
Furthermore, all relevant Ex informations and the specifications of the certificates
can always be obtained from your E+H representative.
Sensor Equipment of transmitter
Promag F
DN 15...300
Promag F
DN 350...2000
•Power pack board
85...260 V AC
or
•Power pack board
20...55 V AC,
16...62 V DC
•Amplifier board with
Pulse output
Current output
Status output
Auxiliary input
•Local display
ba028y02
Fig. 2
1. System Description Promag 31
6 Endress+Hauser

The measuring equipment comprises:
•Transmitter Promag 31 and
•Sensor Promag F
Remote-mounted version (FS version or FL version)
The transmitter is mounted remote from the sensor:
FS version
•Up to 10 m distance meduim conductivity
min. 5 µS/cm
•From 10…200 m distance max. cable length in terms
of the medium conductivity
(5...200 µS/cm)
FL version
•Max. cable length 200 m, not dependent on
conductivity.
•No EPD available.
•The electrical connection between transmitter and
sensor is made in the connection housing
Compact version:
The Promag 31 transmitter
and the sensor together form
a mechanical unit.
Promag F
Promag 31Promag 31 F
ba028y03
Fig. 3
Promag 31 1. System Description
Endress+Hauser 7

1.4 Design of the measuring system
Special points in the non fiscal use
•After the official calibration inspection of the measuring system, the clutch of the
leaded screw (Electronics compartment, Diagram) is sealed. Operation of this
measurement system with these DIP switches (page 33) or above the displays keys
(page 36) is not possible afterwards.
•After every application of the power supply, also with the first service inspection,
“Error” flashes on the display, as an indication of voltage drop. The system remains
in normal measurement mode and the status output is not activated. The same
applies to failure mode, that happens sporadically whilst in service. The flashing dis-
play section is deleted by activating the auxiliary input.
•The system totalises bidirectionaly, during which the pulse and current output
remains unidirectional.
•In fiscal use the periodical electrode cleaning is not possible.
•The auxiliary input, in contrast to “normal” use, is configured to suspend for the
second stage of interuption on the display like for the trigger of the display tests.
A measuremement calculation under pressure or the interuption of the totalisers is
not possible through the auxiliary inputs.
•Status output and auxiliary input must be wired by the user of the system.
Cable entry
Measuring
electrodes
Reference electrode
Screw cover of electronic
compartment (6 parameters can
be set here with internal miniature
switches)
Option: local display
Empty pipe
detection electrode
Outputs*
Current output active
galvanically separated
0/4...20 mA
RL ≤700 Ω
Pulse output Open Collector, passive
galvanically separated
0...400 Hz
Status output Open Collector, passive
galvanically separated
configurable for:
•output of system or process errors
•detection of the direction of flow (not available with fiscal metering
measurement system)
Auxiliary input The auxiliary voltage to be applied
to activate the function is in the region of 3...30 V DC
•External reset in case of error. (Reset-button must be supplied by the end
customer)
•Self test function through the displays has a 10 second duration
* Technical data: see Chapter 6
Sensor
Screw cover
Terminal compartment
Power supply*
85...260 V AC 45...65 Hz
20... 55 V AC
16... 62 V DC
ba028y04
Fig. 4
1. System Description Promag 31
8 Endress+Hauser

Operation
Inside the housing of the transmitter there are miniature switches with which
altogether six operating parameters can be set (see Chapter 4):
•Current range 0/4...20 mA
•Full-scale value scaling (volume/time), 8 steps
•Pulse weighting in decadic steps (volume), 8 steps
•Engineering units
•Function of the status output
Output of system/process errors
Flow direction recognition
•Creep suppression (on/off)
Local display
Using the Promag 31 local display, important parameters can be read off and control-
led at the measuring point directly:
•Flow rate and/or totaliser value
•Technical units (SI/US units)
(US-conformity with fiscal measuring systems is not available)
•Process variables (e.g. creep rate, partial pipe filling)
•Error messages
Using the three operating keys, it is also possible to select and activate various
functions. A small pin is used to press the keys down (keep pressed for
approx. 0.5...0.8 s).
•After the unit has been certified for fiscal metering, it is sealed and it is not possible
to self programe the unit.
Dynamic response
The Promag 31 measuring amplifier has a very high dynamic response of over
1000:1. It measures at medium velocities from less than 10 mm/s to over 10 m/s with
the specified accuracy. When the flow is pulsating, the amplifier is not over-driven
even above the end value setting at maximum speeds up to 12.5 m/s. There is then
no falsification of the measured value, provided the outputs are not over-driven.
Fiscal acceptance
Note!
Fiscal, magnetic-inductive flow meters may (in contrast to mechanical meters) be
operated with Q100 = Qmax.
Warning!
Only a custody transfer certified flowmeter can be used for cold water fiscal metering.
Fiscal-capability
Note!
Fiscal-capable flowmeters for custody transfers are not approved of by the standards
authority. These meters are however technically identical to fiscal flowmeters.
These meters may not be used in fiscal-bound custody transfers.
The fiscale-capable flowmeter can however can be examined and approved of by an
official standards authority through discussion at a later point in time.
Mass-measuring systems with a maximum flow of >2000 m3/h are exempted from
fiscal-standards. These measuring systems will not be fiscal, but they could be
fiscal-capable.
Promag 31 1. System Description
Endress+Hauser 9

Memory (DAT)
DAT is an exchangeable memory module. Stored in it are all characteristic data of the
sensor, such as calibrated quantities, nominal diameter, sensing rate, version, serial
number. When the transmitter has been changed, the previous DAT memory is in-
serted in the new transmitter. When the measuring system is started, the measuring
point continues to operate with the data stored in the DAT memory. Thus the DAT
concept assures maximum safety and optimum ease of operation when components
of the equipment are exchanged.
After calibration
The user of a fiscal Promag 31 measuring system is obligated to insure that the
perscribed standards have been adhered to.
Safety
•A comprehensive self-monitoring facility of the measuring system assures high
safety. Any system error messages (coil-current error, amplifier error, DAT error,
EEPROM error, ROM error, RAM error) or a power supply failure that do occur are
emitted at the configured status output.
•In the event of a power supply failure all data of the measuring system are securely
stored in the EEPROM (without a backup battery).
•The Promag 30 measuring system fulfils the safety requirements according to
EN 61010 “Protection Measures for Electronic Equipment for Measurement,
Control, Regulation and Laboratory Procedures”, and the general requirements
for electromagnetic compatibility (EMC) according to EN 50081 Part 1 and 2 /
EN 50082 Part 1 and 2 as well as the NAMUR recommendations.
•IP 67 protection (EN 60529) is standard for the transmitter and sensor (remote or
compact version). The sensor is also optionally available in IP 68.
1. System Description Promag 31
10 Endress+Hauser

2. Mounting and Installation
Caution!
•Pay consistent attention to the notes in this chapter regarding to assure reliable
measurement.
•For explosion protected instruments the mounting regulations and the technical
data may differ from those stated here. Please refer to the Ex supplement of this
operating manual.
2.1 General Information
Type of protection IP 67 (EN 60529)
The instruments fulfils all requirements for IP 67. In order to assure the type of
protection IP 67 after installation in the field or servicing, it is essential to comply
with the following points:
•The housing gaskets must be clean
and undamaged when inserted in the
sealing groove. If necessary, the
gaskets must first be dried, cleaned
or renewed.
•All screws in the housing and the
screw cover must be screwed up
tight.
•The cables used for connection must
possess the stipulated outside
diameter (see Chapter 6.3).
•Tighten the cable entry (see Fig. 5).
•Loop the cable before inserting. This
prevents moisture from penetrating
the cable entry (see Fig. 5).
•Any cable entries not used must be
stopped with a screw plug.
•The protective grommet must not be
removed from the cable entry.
Caution!
The screws of the Promag sensor housing must not be released, otherwise the
guarantee for the type of protection expires.
Note!
The sensor Promag F can optionally be supplied with the type of protection IP 68
(permanently under water to a depth of 3 m). In this case the transmitter (IP 67) has to
be mounted remote from the sensor.
Temperature ranges
•The maximum permissible ambient and medium temperatures must be adhered to
(see Chapter 6 “Technical Data”).
•When installed outdoors, specially in countries with high ambient temperatures,
a weatherproof hood should be provided as protection against direct solar
radiation.
ba028y05
Fig. 5
Promag 31 2. Mounting and Installation
Endress+Hauser 11

2.2 Transport instructions for Promag from DN 350 / 14"
The pipe lining on the flanges is protected by disks to prevent damage when
transporting to the installation point. These are to be removed before installation.
The instruments are to be transported in the containers they are delivered in.
Transporting to the measuring point
The grips on the flange must be used for
lifting out and mounting the sensor in the
piping.
The sensor should not be lifted by the
connection housing.
The sensor should not be lifted by the
sheet casing using a forklift truck.
This can buckle the casing and damage
the internal magnetic coils.
Base of the sensor
The sensor should stand on a base
which is sufficiently strong to withstand
its weight.
Note!
The sensor must not be supported by
the sheet casing! This can buckle the
casing and damage the internal mag-
netic coils.
ba028y60
Fig. 6
ba028y61
Fig. 7
ba028y62
Fig. 8
ba028y64
Fig. 9
ba028y63
2. Mounting and Installation Promag 31
12 Endress+Hauser

2.3 Mounting Instructions
Please pay attention to the following instructions, in order that you may measure
correctly and avoid damage to the equipment.
Mounting position (any)
a) Vertical mounting:
Optimal, with the flow upwards.
Entrained solid particles sink and
lighter fatty elements in the
stationary medium rise away from
the electrodes.
b) Horizontal mounting:
The axis of the electrodes must
be horizontal, thus preventing brief
insulation of the electrodes by
entrained air bubbles.
Vibration
Fasten the piping before and after the
sensor.
Caution!
Excessive vibration necessitates
separate mounting of the sensor and
transmitter (see Chapter 2.6).
With free runs of piping over 10 m long,
we recommend mechanical supports.
ba028y07
a)
b)
Fig. 10
ba028y08
>10 m
Fig. 11
Promag 31 2. Mounting and Installation
Endress+Hauser 13

Inlet and outlet runs
The sensor should be mounted away
from fittings liable to generate
turbulence (e.g. valves, elbows,
T-junctions).
Inlet run: > 3...5 x DN
Outlet run: > 2 x DN
For fiscal use, the straight pipe
requirements are 5 x DN upstream and
2 x DN downstream, measured from the
meter flanges.
Mounting location
Correct measurement is only possible
when the pipe is full. Consequently the
following locations should be avoided:
No installation at the highest point
(air accumulation).
No installation immediately before an
open pipe outlet in a downward line. The
installation shown in Fig. 13, however,
permits such a location.
Partly filled pipes
For inclines a mounting similar to a drain
should be adopted. Do not mount at the
lowest point (risk of solids collecting).
Added security is offered by Empty Pipe
Detection (EPD). This option has an
extra electrode in the measuring pipe
(standard with Promag F sensor).
Note!
Here, too, the inlet and outlet lengths
should be maintained.
DN = pipe diameter
> 3...5 x DN > 2 x DN
ba028y09
Fig. 12
ba028y10
h > 2 x DN
Fig. 13
> 3...5 x DN
> 2 x DN
ba028y11
Fig. 14
2. Mounting and Installation Promag 31
14 Endress+Hauser

Downward pipe (>5 m)
With the suggested installation opposite
(siphon, vent valve after the sensor) no
partial vacuum is created with such a
downward pipe >5 m long.
Installation of pumps
If possible avoid mounting the sensor on
the suction side of the pump (danger of
vacuum!). Information on the resistance
to vacuum of the measuring pipe lining
can be found on Chapter 6.2.
Adaptor pieces
The sensor can also be mounted in a
pipe with a larger nominal diameter
when suitable adaptors (reducers and
expanders) to DIN 28545 are fitted. The
resultant increase in the rate of flow
increases the accuracy of measurement
with slowly flowing fluids.
The adjacent nomogram can be used to
determine the pressure loss caused.
Procedure:
1. Determine the ratio of the diameters
d/D.
2. From the nomogram read off the
pressure loss at the flow velocity and
d/D ratio.
Note!
The nomogram applies to fluids with a
viscosity similar to that of water.
Vent valve
ba028y12
>5 m
Fig. 15
ba028y13
Fig. 16
max. 8°
dD
ba028y14
Pressure loss in [mbar]
Diameter ratio d/D
Fig. 17
Promag 31 2. Mounting and Installation
Endress+Hauser 15

2.4 Mounting Promag 31 F
Lengths and dimensions
See Chapter 6.1 “Dimensions and weights”
Mounting
The sensor is mounted between the flanges of the pipe (see Fig. 18). Since the lining
of the measuring pipe is drawn on over the sensor flange, it performs the sealing
function at the same time.
Caution!
The Teflon (PTFE)-lined measuring pipe of the Promag F is fitted with protective discs
to guard the liner which is turned over the flanges. These discs may only be removed
just before mounting the sensor, thereby making sure that the liner is not damaged at
the flange or removed (during storage these discs must remain in position).
Screw tightening torques
•The listed tightening torques
apply to greased threads.
•Screws tightened up too tightly
deform the sealing surface (pay
special attention with soft rubber
lining).
Gaskets
•With soft rubber/Teflon (PTFE)
linings a flange gasket can be
dispensed with.
•With soft rubber linings the mat-
ing flange should have a thin film
of sealing grease applied.
•Use a gasket as per DIN 2690.
Caution!
Do not use sealing media that is
electrically conductive, e.g.
graphite. On the inside of the
measuring pipe this could result in
an electrically conductive layer
forming which would short-circuit
the measuring signal.
DN Pressure
stages Screws Max. tightening torque [Nm]
DIN
[mm] ANSI [inch] DIN [bar] Hard rubber Soft rubber
(EPDM)
Teflon
(PTFE)
15
25
32
40
50
1/2"
1"
-
11/2"
2"
PN
40
4 x M 12
4 x M 12
4 x M 16
4 x M 16
4 x M 16
-
25
40
50
64
-
5
8
11
15
15
33
53
67
84
65
80
100
125
150
200
-
3"
4"
-
6"
8"
PN
16
4 x M 16
8 x M 16
8 x M 16
8 x M 16
8 x M 20
8 x M 20
87
53
65
80
110
108
22
14
22
30
48
53
114
70
85
103
140
137
250
300 10" 12" PN 10 12 x M 20 12 x M 20 104 119 29 39 139 159
350
400
-
500
600
14"
16"
18"
20"
24"
PN
10/16
16 x M 20
16 x M 24
20 x M 24
20 x M 24
20 x M 27
141/193
191/245
170/251
197/347
261/529
39/79
59/111
58/111
70/152
107/236
188/258
255/326
227/335
262/463
348/706
700
800
900
1000
28"
30"
32"
36"
PN
10/16
24 x M 27
24 x M 30
28 x M 30
28 x M 33
312/355
417/471
399/451
513/644
122/235
173/330
183/349
245/470
-
-
-
-
1200
-
1400
-
1600
-
1800
-
2000
48"
54"
-
60"
-
66"
72"
78"
-
PN
6
32 x M 36
36 x M 39
36 x M 39
40 x M 45
40 x M 45
44 x M 45
44 x M 45
48 x M 45
48 x M 45
720
840
840
1217
1217
1238
1238
1347
1347
328
432
432
592
592
667
667
749
749
-
-
-
-
-
-
-
-
-
ba028y17
Fig. 18
2. Mounting and Installation Promag 31
16 Endress+Hauser

Replacement measuring electrodes
Dismantling the electrode:
1. Loosen the Allen screws (a) of the cap/cover.
2. Unscrew the electrode cable (c) attached to the
rotary arm (b).
3. Undo the knurled nut (d) by hand. This nut is
used as a counter nut.
4. Remove the electrode (e) using the rotary arm
(b). This can now be taken out from the holder
(g) as far as the stop allows.
Warning!
The electrode can spring back to the
stop. Keep pressing against it
while loosening.
5. Close the shut-off valve (f) after the electrode
has been taken out as far as the stop.
Warning!
Do not attempt to open the shut-off
valve. Keeping it shut prevents
medium from escaping.
6. Unscrew the entire electrode along with the
holding cylinder (g).
7. Remove the pins (h) below the rotary arm.
8. Replace electrode with a new one.
A set of new electrodes can be ordered from
E+H.
Assembling the electrode:
1. Slide the new electrode (e) through the holding
cylinder (g) from below.
Gaskets at the tip of the electrode must be in
place and clean.
2. Connect the rotary arm (b) and electrodes
together using the pins (h). Ensure that the
small coil spring is in place.
3. Pull back the electrode as far as possible so
that the tip does not protrude out from the hold-
ing cylinder (g).
4. Screw the holding cylinder onto the shut-off unit
(I) and tighten by hand.
Note!
Gasket (j) on the holding cylinder
must be in place and clean.
5. Open the shut-off value (f) and screw in the
electrode using the rotary arm (b). Pull the elec-
trode on by hand.
6. Screw the knurled nut (d) onto the holding cylin-
der in order to clamp the electrode tight.
7. Secure the electrode cable (c) to the rotary arm
using the Allen screw.
Caution!
Ensure that the Allen screw of the
electrode cable is tight. A close
electrical contact cannot otherwise
be guaranteed and this can lead to
measurement errors.
The Promag F Type DN 350...DN 600 is available with replacement electrodes.
This version enables the measuring electrodes to be cleaned or replaced under process conditions.
Replacing an electrodes is carried out as follows:
ba028y67
a
h
f
i
b
d
g
a
j
e
cright side:
Type DN 350...600
Fig. 19
Promag 31 2. Mounting and Installation
Endress+Hauser 17

2.5 Turning the transmitter housing and local display
(compact version)
In the compact version the transmitter housing and the local display can be rotated in
steps of 90° relative to the sensor. This enables the unit to be adapted to suit the
various mounting positions in the pipe.
Note!
For instruments with EEx d/de approval the procedure for rotating the instrument
is different than that described here and is given in the Ex supplement to this manual.
Turning the transmitter housing
1. Loosen the two fixing screws of the transmit-
ter bayonet catch (appr. 2 turns).
2. Turn the bayonet catch of the transmitter as
far as the screw slits.
3. Lift the transmitter housing to the stop.
Note!
During servicing (and only then) the trans-
mitter housing can be separated from the
sensor. To do this the corresponding mark-
ing notches on the side of the bayonet
flanges should be brought into alignment.
Do not damage the cable to the sensor
when lifting the transmitter housing.
4. Turn the transmitter housing into the desired
position. Engage the bayonet catch and
re-tighten the two screws.
ba028y18
Fig. 20
Turning the local display
Warning!
Danger from electric shock. Switch off the
power supply, before unscrew the cover of
electronics area.
1. Loosen the safety grip of the cover of the
electronics area. Loosen the screw with
a 3 mm Allen key.
2. Unscrew the cover of the electronics area
of the transmitter housing.
3. Unscrew the two Phillips screws which
fasten the display module.
4. Rotate the display module to the required
position.
5. Securely tighten the Phillips screws.
6. Replace and screw down securely the
cover of the electronics area of the transmit-
ter housing.
7. Replace and tighten the safety grip.
ba028y19
Fig. 21
2. Mounting and Installation Promag 31
18 Endress+Hauser

2.6 Mounting the transmitter (remote-mounted version)
It is necessary to mount the transmitter remote from the sensor when:
•Accessibility is difficult
•Space is restricted
•Extreme medium and ambient temperatures prevail
(for temperature ranges see Chapter 6 “Technical Data”)
•Severe vibration (>2 g/2 h per day; 10...100 Hz)
Caution!
•The permissible length of cable Lmax between the sensor and the transmitter at a
distance of >10 m is governed by the conductivity of the medium (Fig. 22).
•Fix the cable run or lay it in conduit. When the conductivity of the medium is low,
cable movements can cause serious changes in capacitance and thereby falsify
the measuring signal.
•Do not lay cable in the vicinity of electrical machines or switching elements.
•Pay attention to potential equalization between the transmitter and the sensor.
•Please connect the cable as described on page 23.
Conductivity
[µS/cm]
ba028y20
Transmitter housing
Wiring compartment
connection housing
Wall holder
Length of cable for the remote-mounted version (FS and FL)
Permissible
range
Cable length Lmax [m]
Fig. 22
Fixing the wall holder/Stamped lead seal
Compact version Remote version
Sealing of compact versions
The cover of the electronic compart-
ment of the Promag 31 is separetly
sealed. Instead of the conventional
cylindric screws a leading screw is
used and the seal wire is drawn
through it and fixed under the clutch.
Stamped lead seal for remote version
(Promag 31 F for example)
In addition to the above mentioned
and described seal the connection
housing in both the sensor and the
electronics will be lead sealed after in-
stallation by the service man with a
user protection (sealed from works).
Sealing by
authorised
institution Sealing
after the
installation
ba028yt7
Fig. 23
Promag 31 2. Mounting and Installation
Endress+Hauser 19

2.7 Potential equalisation
The sensor and the medium must have
roughly the same electrical potential to
ensure that measurement is accurate
and no galvanic corrosion takes place
at the electrodes. Normally the refer-
ence electrode in the sensor or the met-
al pipe ensures that the potentials are
equalized. With an existing reference
electrode and for media carried in ear-
thed metal piping it is therefore suffi-
cient to connect the earthing terminal of
the Promag 31 transmitter housing to
the potential equalizing line.
With the remote-mounted version this
connection is made at the earth terminal of the connection housing (transmitter).
Fig. 24 shows the reference electrode in the sensor Promag F.
Potential equalisation for some special cases is described below:
Potential equalisation for lined
pipes with cathodic protection
When the medium cannot be earthed
for operational reasons, the measuring
unit must be installed that it is potential-
free (Fig. 25).
Please pay attention to national regula-
tions regarding potential-free installation
(e.g. VDE 0100).
It is also important to ensure that the
mounting material used does not result
in a conductive bond with the measur-
ing unit and that the material can
withstand the tightening torque used.
Plastic or lined piping
This arrangement (Fig. 26) is needed if
there is no reference electrode present
or the medium has to be earthed on
account of equalizing currents.
Caution!
Make sure the earthing discs are
corrosion-resistant.
Measuring electrodes
Reference electrode
ba028y22
Measuring pipe
Fig. 24
6 mm2Cu
Electrically
insulated
Electrically
insulated
Isolating transformer
Supply
ba028y23
Fig. 25
Earthing discs: appr. 3 mm thick
ba028y24
6 mm2Cu
Fig. 26
2. Mounting and Installation Promag 31
20 Endress+Hauser