TVA Flowmeter for Saturated and Superheated Steam Service

TVA Flowmeter for Saturated and Superheated Steam Service
1920050/1
IM-P192-02
MI Issue 1
TVA Flowmeter
for Saturated and Superheated Steam Service
Installation and Maintenance Instructions
1.Safety information
2.General
product information
3.Installation
4.Commissioning
5.Operation
6.Maintenance
7.Spare parts
8.Fault finding
9.Settings table
IM-P192-02 MI Issue 1
© Copyright 2014
1
Printed in GB
Certain computer programs contained in this product [or device] were developed by
Spirax-Sarco Limited ('the Work(s)').
Copyright © Spirax-Sarco Limited 2014
All rights reserved
Spirax-Sarco Limited grants the legal user of this product (or device) the right to use
the Work(s) solely within the scope of the legitimate operation of the product (or device).
No other right is granted under this licence. In particular and without prejudice to the
generality of the foregoing, the Work(s) may not be used, sold, licensed, transferred,
copied or reproduced in whole or in part or in any manner or form other than as
expressly granted here without the prior written consent of Spirax-Sarco Limited.
2
IM-P192-02 MI Issue 1
1. Safety information
Safe operation of this unit can only be guaranteed if it is properly installed,
commissioned and maintained by a qualified person (see Section 1.11) in compliance
with the operating instructions. General installation and safety instructions for
pipeline and plant construction, as well as the proper use of tools and safety
equipment must also be complied with.
Manufacturer:Spirax Sarco Ltd
Charlton House
Charlton Kings
Cheltenham
Glos
GL53 8ER
The product is designed and constructed to withstand the forces encountered
during normal use. Use of the product for any other purpose, or failure to install the
product in accordance with these Installation and Maintenance Instructions, could
cause damage to the product, will invalidate the
marking, and may cause injury or
fatality to personnel.
EMC directive
The product complies with the Electromagnetic Compatibility Directive 2004 / 108 / EC.
A technical file with a reference number of 'UK Supply TVA flowmeter' supports the
Spirax Sarco claim that the product complies with the requirements of the Directive
and the product can be used in Class A (heavy industrial) and Class B (domestic / commercial areas).
The following conditions should be avoided as they may create interference above
the heavy industrial limits if:
- The product or its wiring is located near a radio transmitter.
- Cellular telephones and mobile radios may cause interference if used within
approximately 1 metre (39") of the product or its wiring. The actual separation
distance necessary will vary according to the surroundings of the installation
and the power of the transmitter.
If this product is not used in the manner specified by this IMI, then the protection
provided may be impaired.
1.1Intended use
Referring to the Installation and Maintenance Instructions, name-plate and Technical
Information Sheet, check that the product is suitable for the intended use / application.
The product listed complies with the requirements of the European Pressure
Equipment Directive 97 / 23 / EC, carries the
mark when so required. The product
falls within the following Pressure Equipment Directive categories:
Product
TVA flowmetering
system
DN50 to DN100
Group 1
Gases
Group 2
Gases
Group 1
Liquids
Group 2
Liquids
-
1
-
-
i) The product has been specifically designed for use on saturated and superheated
steam only which is in Group 2 of the above mentioned Pressure Equipment
Directive.
IM-P192-02 MI Issue 1
3
ii) Check material suitability, pressure and temperature and their maximum
and minimum values. If the maximum operating limits of the product are lower than
those of the system in which it is being fitted, or if malfunction of the product
could result in a dangerous overpressure or overtemperature occurrence, ensure
a safety device is included in the system to prevent such over-limit situations.
iii) Determine the correct installation situation and direction of fluid flow.
iv) Spirax Sarco products are not intended to withstand external stresses that
may be induced by any system to which they are fitted. It is the responsibility of
the installer to consider these stresses and take adequate precautions to
minimise them.
v) Remove protection covers from all connections and protective film from all nameplates, where appropriate, before installation on steam or other high temperature
applications.
1.2 Access
Ensure safe access and if necessary a safe working platform (suitably guarded)
before attempting to work on the product. Arrange suitable lifting gear if required.
1.3 Lighting
Ensure adequate lighting, particularly where detailed or intricate work is required.
1.4 Hazardous liquids or gases in the pipeline
Consider what is in the pipeline or what may have been in the pipeline at some
previous time. Consider: flammable materials, substances hazardous to health,
extremes of temperature.
1.5 Hazardous environment around the product
Consider: explosion risk areas, lack of oxygen (e.g. tanks, pits), dangerous gases,
extremes of temperature, hot surfaces, fire hazard (e.g. during welding), excessive
noise, moving machinery.
1.6 The system
Consider the effect on the complete system of the work proposed. Will any proposed
action (e.g. closing isolation valves, electrical isolation) put any other part of the
system or any personnel at risk?
Dangers might include isolation of vents or protective devices or the rendering
ineffective of controls or alarms. Ensure isolation valves are turned on and off in a
gradual way to avoid system shocks.
1.7 Pressure systems
Ensure that any pressure is isolated and safely vented to atmospheric pressure.
Consider double isolation (double block and bleed) and the locking or labelling of
closed valves. Do not assume that the system has depressurised even when the
pressure gauge indicates zero.
1.8 Temperature
Allow time for temperature to normalise after isolation to avoid the danger of burns
and consider whether protective clothing (including safety glasses) is required.
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IM-P192-02 MI Issue 1
1.9 Tools and consumables
Before starting work ensure that you have suitable tools and / or consumables
available. Use only genuine Spirax Sarco replacement parts.
1.10 Protective clothing
Consider whether you and /or others in the vicinity require any protective clothing
to protect against the hazards of, for example, chemicals, high / low temperature,
radiation, noise, falling objects, and dangers to eyes and face.
1.11 Permits to work
All work must be carried out or be supervised by a suitably competent person.
Installation and operating personnel should be trained in the correct use of the
product according to the Installation and Maintenance Instructions.
Where a formal 'permit to work' system is in force it must be complied with. Where
there is no such system, it is recommended that a responsible person should know
what work is going on and, where necessary, arrange to have an assistant whose
primary responsibility is safety.
Post 'warning notices' if necessary.
1.12 Handling
Manual handling of large and /or heavy products may present a risk of injury. Lifting,
pushing, pulling, carrying or supporting a load by bodily force can cause injury
particularly to the back. You are advised to assess the risks taking into account the
task, the individual, the load and the working environment and use the appropriate
handling method depending on the circumstances of the work being done.
1.13 Residual hazards
In normal use the external surface of the product may be very hot. If used at the
maximum permitted operating conditions the surface temperature of some products
may reach temperatures of 250°C (482°F).
Many products are not self-draining. Take due care when dismantling or removing
the product from an installation (refer to 'Maintenance instructions').
1.14 Freezing
Provision must be made to protect products which are not self-draining against
frost damage in environments where they may be exposed to temperatures below
freezing point.
1.15 Disposal
Unless otherwise stated in the Installation and Maintenance Instructions, this
product is recyclable and no ecological hazard is anticipated with its disposal
providing due care is taken.
1.16 Returning products
Customers and stockists are reminded that under EC Health, Safety and Environment
Law, when returning products to Spirax Sarco they must provide information on
any hazards and the precautions to be taken due to contamination residues or
mechanical damage which may present a health, safety or environmental risk. This
information must be provided in writing including Health and Safety data sheets
relating to any substances identified as hazardous or potentially hazardous.
IM-P192-02 MI Issue 1
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2. General product information
This manual explains how to install, commission and maintain the Spirax Sarco TVA flowmeter
for use on saturated and superheated steam.
2.1 Product description
The Spirax Sarco TVA flowmeter is designed to reduce the cost of flowmetering and is used
as an accurate means to measure steam flowrates and record total flow.
For saturated steam installations the TVA flowmeter is a stand alone device and requires no
other equipment, such as differential pressure transmitters, pressure sensors, etc. to calculate
mass flowrates of saturated steam.
With superheated steam installations, the addition of the pressure sensing kit is required to
enable mass flowrates to be measured where the relation between pressure and temperature has been lost (steam saturation curve).
2.2 Equipment delivery and handling
Factory shipment
Prior to shipment, the Spirax Sarco TVA flowmeter is tested, calibrated and inspected to
ensure proper operation, including the wired communications.
Receipt of shipment
Each carton should be inspected at the time of delivery for possible external damage. Any
visible damage should be recorded immediately on the carrier’s copy of the delivery slip.
Each carton should be unpacked carefully and its contents checked for damage.
If it is found that some items have been damaged or are missing, notify Spirax Sarco
immediately and provide full details. In addition, damage must be reported to the carrier with a
request for their on-site inspection of the damaged item and its shipping carton.
Storage
If a flowmeter is to be stored prior to installation, the environmental storage conditions
should be at a temperature between 0°C and 55°C (32°F and 131°F), and between 10% and
90% relative humidity (non-condensing).
2.3 Sizes and pipe connections
DN50, DN80 and DN100
The TVA flowmeter is of a wafer design, suitable for fitting between the following flanges:
EN 1092 PN16, PN25 and PN40
BS 10 Table H
ASME B 16.5 Class 150 and 300
Korean Standard KS 20.
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IM-P192-02 MI Issue 1
* Sensor cable
* Pressure sensor
TVA flowmeter body
Earth
cable
¼"
NPSM
boss
Fl o w
Flowmeter stem
* 'U' syphon assembly
Earth
cable
* Items required for superheat operation
Fig. 1 TVA flowmeter
IM-P192-02 MI Issue 1
Electronics housing
7
2.4 Pressure / temperature limits
Temperature °F
Temperature °C
Pressure psi g
Steam
saturation
curve
Pressure bar g
The product should not be used in this region due to the limitations of the software.
PMA
Maximum allowable
pressure @ 239°C (462°F)
Saturated steam 32 bar g (464 psi g)
otherwise as the specified flange rating
TMA
Maximum allowable temperature
Minimum allowable temperature
PMO
Maximum
operating
pressure for
saturated
steam
service
Horizontal
flow
Vertical flow
0°C (non-freezing)
(32°F non-freezing)
(333 psi g @ 462°F)
Saturated
steam
32 bar g @ 239°C
(464 psi g @ 462°F)
Saturated
steam only
7 bar g @ 170°C
(101 psi g @ 338°F)
0.6 bar g
(8.7 psi g)
239°C
(462°F)
0°C (non-freezing)
(32°F non-freezing)
55°C
(131°F)
Maximum operating temperature
Minimum operating temperature
Maximum electronics ambient temperature
Maximum electronics humidity level
Maximum
PMX differential
pressure
(462°F)
Superheated 23 bar g @ 239°C
steam
Minimum operating pressure
TMO
239°C
90% RH (non-condensing)
The pressure drop across the TVA flowmeter at the maximum
rated flow is nominally 750 m bar (300 inches wg) for the DN50,
and 500 m bar (200 inches wg) for the DN80 and DN100
Cold hydraulic test pressure of:
52 bar g
(754 psi g)
80 bar g
(1 160 psi g)
450°C
(842°F)
60 bar g @ 450°C
(870 bar g @ 842°F)
Maximum operating temperature
125°C
(257°F)
Minimum operating temperature
0°C (non-freezing)
(32°F non-freezing)
50 bar g
(725 psi g)
70°C
(158°F)
High pressure syphon tube assembly
Maximum design pressure
Maximum design temperature
Maximum working conditions
Pressure sensing kit
Maximum operating pressure
Maximum ambient temperature (cable+connector)
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IM-P192-02 MI Issue 1
*
Limited to
7 bar g (101 psi g)
and
saturated steam
applications
only
* Important note
CAUTION:
If the electronic housing is mounted
at an angle of more than 45° from the
vertically downward position the PMO
(maximum operating pressure) must be
limited to 7 bar g (101 psi g) and
saturated steam applications only.
The electronic housing must be
mounted vertically downward for all
superheated applications.
For saturated steam
applications
over 7 bar g (101 psi g)
to 32 bar g (464 psi g) and all
superheated applications up to
23 bar g (333.5 psi g).
Fig. 2 Installation limiting conditions
2.5 Technical data
IP rating
Power supply Outputs
Communication port
System uncertainty
Performance to ISO 17025
(95% confidence to 2 STD)
IP65 with correct cable glands.
Loop powered nominal 24 Vdc
4-20 mA (proportional to mass flow)
Pulsed output Vmax 28 Vdc, Rmin 10 kW,
Von 0.7 Vmax
EIA 232C 15 m limit - See Section 4.12
±2% of reading over the range of 10% to
100% of maximum rated flow
±0.2% FSD from 2% to 10% of maximum rated flow
Turndown: up to 50:1
2.6 Electrical connections
Electrical connections
IM-P192-02 MI Issue 1
M20 x 1.5
9
2.7 Materials
Unit
TVA
Part
Material
Flowmeter body
Stainless steel S.316 1.4408 CF8M
Internals
431 S29 / S303 / S304 / S316
Spring
Inconel X750 or equivalent
Flowmeter stem
Stainless steel 300 series
Electronics housing Aluminium LM25
Pressure
sensing kit
High pressure
syphon tube
assembly
10
Cable
Polyvinyl chloride (PVC)
Sensor housing
AISI 304 Stainless steel 1.4301
Sensor
AISI 630 Stainless steel 1.4542
'O' ring
Nitrile Butadiene Rubber (NBR)
Adaptor
AISI 431 Stainless steel 1.4057
Tube
Carbon steel BS 3602: Part.1 1987 CFS 360
(zinc plated / passivated).
Body
Carbon steel
Seat
PEEK/ Polymain
Valve
IM-P192-02 MI Issue 1
2.8 Dimensions /weights (approximate) in mm and kg
Size
A Flowmeter
OD
DN50
35
DN80
45
138
DN100
60
162
103
Weight
Superheat
'U'
kit
syphon
C
D
E
F
G
X
TVA
322
125
65
250
160
300
2.67
0.3
0.5
334
115
65
270
160
300
4.38
0.3
0.5
344
155
65
280
160
300
7.28
0.3
0.5
Note: Dimension 'X' is a recommended minimum distance between the pressure tapping
and the flowmeter. However it can be installed at any distance provided the cable allows
(Standard cable length is 1 m).
A
D
X
Caution:
Any free hanging cable must be
secured to prevent contact with
the steam pipe.
Fig. 3
G
F
C
E
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3. Installation
Note: Before actioning any installation observe the 'Safety information' in Section 1.
To meet its specified accuracy and performance it is essential that the following installation
guidelines are followed carefully. For steam applications sound steam engineering practices
should be followed, including the use of separators. The installation must conform to all
relevant construction and electrical codes.
Limited to
7 bar g (101 psi g)
and
saturated steam
applications
only
CAUTION:
If the electronic housing is mounted
at an angle of more than 45° from the
vertically downward position the PMO
(maximum operating pressure) must be
limited to 7 bar g (101 psi g) and
saturated steam applications only.
The electronic housing must be
mounted vertically downward for all
superheated applications.
For saturated steam
applications
over 7 bar g (101 psi g)
to 32 bar g (464 psi g) and all
superheated applications up to
23 bar g (333.5 psi g).
Fig. 4 Installation limiting conditions
A bypass line will enable safe removal of the TVA flowmeter for maintenance or calibration.
Closing valves V1 and V2 and opening valve V3 will allow the TVA flowmeter to be
isolated for re-zeroing (temperature to be <20°C).
V3
Strainer
Steam
Separator
Trap set
V1
V2
TVA
flowmeter
with
Superheat kit
fitted
Spool
piece
Fig. 5 Typical installation
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IM-P192-02 MI Issue 1
3.1 Environmental conditions
The flowmeter should be located in an environment that minimises the effects of heat, vibration,
shock and electrical interference. (Pressure / temperature limits are detailed in Section 2.4).
CAUTION: Do not lag (insulate) the TVA flowmeter or mating flanges as this may
result in excessive temperatures in the electronics. Exceeding specified temperature
limits will invalidate the warranty, adversely effect the performance and may damage
the TVA flowmeter, see Figure 6.
Do not
insulate the flanges of the TVA flowmeter
Flow
Fig. 6 Pipeline insulation
Other considerations
Be sure to allow sufficient clearance for:
- Installation of conduit / wiring.
- Removal of the electronics enclosure cover.
- Viewing of the display. Note electronics housing and display can be rotated.
- Do not allow the earth cable to touch the steam pipe or damage to the sheath will occur.
Tie up any loose (excess) cable.
Warning: Do not install the flowmeter outdoors where it can be subjected to adverse
weather conditions like driving rain or where it can freeze.
IM-P192-02 MI Issue 1
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3.2 Mechanical installation
Warning: Do not alter the adjustment nut at the back of the TVA flowmeter shaft, as
this will affect the flowmeters calibration.
Orientation
The TVA flowmeter can be installed in any orientation when used on saturated steam
applications and when the pressure is below 7 bar g (101 psi g), see Figures 7, 8 and 9.
When the pressure is above 7 bar g (101 psi g) or used on a superheated steam application the
TVA flowmeter must be installed in a horizontal pipe, with the electronics housing below the body,
see Figure 9.
Note: The TVA flowmeter operates with flow in one direction only. It is not intended for use
with bi-directional flow. The TVA flowmeter is clearly marked with a direction of flow arrow.
Flow
Flow
Fig. 7 Vertical flow limited to 7 bar g (101 psi g)
and saturated steam applications only
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IM-P192-02 MI Issue 1
CAUTION: If the electronic housing is mounted at an angle of 45° (or more) from the
vertically downward position the PMO (maximum operating pressure) must be limited
to 7 bar g (101 psi g) and saturated steam applications only.
The electronic housing must be mounted vertically downward for all superheated
applications.
Flow
Fig. 8 Horizontal flow limited to 7 bar g (101 psi g)
and saturated steam applications only
Flow
Note: The 'U' syphon and
pressure sensor must
be used for superheated
steam applications.
Fig. 9 Horizontal flow up to 32 bar g (464 psi g) for saturated steam applications
and 23 bar g (333.5 psi g) for superheated steam applications
IM-P192-02 MI Issue 1
15
Rotating the electronics enclosure
The electronics housing can be rotated 270°
to enable sufficient clearance for installation.
To rotate the electronics housing, loosen the
6 mm grub screw located on the rear of the
electronics housing (see Figure 10). The
electronics housing can now be rotated
to the required position.
When the electronics housing has been located
into the correct position retighten the grub
screw to a torque of 1.3 N m (11.5 lbf in).
Warning: Do not loosen / remove the stem
from the main body of the unit.
Warning: Do not loosen /
remove the stem from the
main body of the unit.
6 mm grub screw
Fig. 10
Earth
cable
Upstream / downstream pipework
The T VA flowmeter should be installed in pipework manufactured to BS 1600,
ASME B 36.10 Schedule 40 or EN 10216-2 / EN 10216-5 equivalent, which corresponds
to the following pipeline internal diameters:
Nominal diameter
50 mm
80 mm
100 mm
Nominal internal diameter
52 mm
77 mm
102 mm
For different pipe standards / schedules, if the flowmeter is being operated at the extreme of its
published maximum range, and maximum accuracy is required, downstream spool pieces
manufactured from pipe to the above standard should be used.
It is important that the internal upstream and downstream diameters of pipe are smooth. Ideally
seamless pipes should be used and there should be no intrusive weld beads on the internal
diameter. It is recommended that slip-on flanges be used to avoid any intrusive weld beads on
the internal diameter of the pipe.
Note: See Figures 11 to 14 for other considerations which need to be noted before
determining the correct installation location.
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IM-P192-02 MI Issue 1
The TVA flowmeter normally only requires a minimum of 6 pipe diameters upstream and
3 downstream of clear straight pipe. These dimensions assume a measurement from a single
90° bend (see Figure 11).
6D Minimum
6D Minimum
3D
3D Minimum
Minimum
Note: The 'U' syphon and
pressure sensor must
be used for superheated
steam applications.
Flow
Fig. 11
If any of the following configurations are present upstream of the TVA flowmeter:
- Two right angled bends in two planes.
- Pressure reducing valve.
- Partly open valve.
Then it is recommended that the minimum upstream clear pipework is doubled to 12 diameters
(See Figure 12).
12D Minimum
Flow
Fig. 12
IM-P192-02 MI Issue 1
3D Minimum
Note: The 'U' syphon and
pressure sensor must
be used for superheated
steam applications.
17
Avoid installing the TVA flowmeter downstream of an actuated valve as rapid cycling
of the valve could give rise to inaccurate results or damage the flowmeter. See Figure 13.
In configurations where there is more than one rapid acting pressure reducing valve
close coupled, the TVA flowmeter should be installed with a minimum of 25 upstream and
3 downstream pipe diameters away from the valves.
Safety valves should also be as far away as possible from the flowmeter - at least 25D.
25D Minimum
3D Minimum
Flow
Fig. 13
18
Note: The 'U' syphon and
pressure sensor must be
used for superheated steam
applications.
IM-P192-02 MI Issue 1
To install the TVA flowmeter pipeline unit into existing pipework and for aiding possible
flowmeter removal, a spool piece can be fabricated locally to the dimensions given below
(see Figure 14).
Size
Dimension A
DN50
DN80
DN100
180 mm
240 mm
300 mm
7.1 in
9.5 in
11.8 in
A
Flow
Spool piece
Fig. 14
IM-P192-02 MI Issue 1
Note: The 'U' syphon and
pressure sensor must be
used for superheated steam
applications.
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Location in pipework
Bolt ring gaskets having the same internal diameter of the pipework are recommended. This
will prevent possible inaccuracies being created by the gasket protruding into the pipe.
It is important that the TVA flowmeter is located centrally in the pipework as any eccentricity
may cause inaccurate readings. The TVA flowmeter has integral centering webs, which locate
on the internal diameter of the pipework (see Figure 15).
Integral centering webs
Integral centering webs
Earth cable
Fig. 15 Integral centering webs
Note: The 'U' syphon and
pressure sensor must
be used for superheated
steam applications.
Fig. 16 Gaskets fitted correctly
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IM-P192-02 MI Issue 1
Fig. 17 Gaskets fitted incorrectly
Fig. 18 Gaskets and pipe offline, fitting incorrectly
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21
3.3 Fitting the pressure sensor for superheated steam applications
To operate the TVA flowmeter on superheated steam the pressure sensor must be installed
upstream of the actual flowmeter. This is to give full density compensation and allow the
amount of superheat to be calculated.
A ¼" NPSM boss will be required on the pipe for the connection of the 'U' syphon and
pressure sensor. It should be sited as close to the upstream flange as practicably possible
(see Figure 19, and take into account dimension 'X' in Section 2.8).
Note: The TVA must only be used for superheated steam application, when the pipe is in
a horizontal plane.
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IM-P192-02 MI Issue 1
* Sensor cable
* Pressure sensor
TVA flowmeter body
Earth
cable
¼"
NPSM
boss
Fl o w
Flowmeter stem
* 'U' syphon assembly
Earth
cable
* Items required for superheat operation
Fig. 19 TVA flowmeter
IM-P192-02 MI Issue 1
Electronics housing
23
3.4 Electrical installation
The TVA flowmeter is a loop powered device. This Section describes loop wiring and shows
typical conductor terminations (The EIA 232C (RS 232) wiring is discussed in Section 4.11,
page 41). It also considers the effect of connecting additional equipment (e.g. recorder,
loop powered display) to the loop, plus the pressure sensor connection.
Wiring the TVA flowmeter
The wiring terminals can be accessed by removing the end cap of the enclosure. A typical loop
wiring diagram is shown in Figure 20.
If an M750 display unit is purchased from Spirax Sarco for use with the TVA flowmeter,
the M750 must be configured to the flow of the TVA flowmeter @ 20 mA. If the TVA flowmeter
4 - 20 mA output is rescaled (see Section 4.6.1), it is important that the 20 mA input valve
on the M750 is also rescaled.
Recommendations:
- Ensure the provided EMC gland is used to connect the wiring to the electronics housing.
- When using the RS232 port, PVC covered steel conduit should be used.
- All cables that run through conduit should be screened. The screens must be earthed at
the far end of the installation and not at the flowmeter.
- If using the loop and switch pulse ports:
- Either combine both port outputs to one screened four core cable which is terminated
with an EMC gland.
- or, use flexible conduit as described above.
Notes:
The flowmeter must be earthed. The TVA is supplied with a 350 mm earthing lead
attached to a 4 mm threaded hole at the rear of the enclosure close to the 20 mm
conduit holes.
Remove the silica gel from the enclosure after commissioning.
When connecting the superheat kit to the TVA, the cable from the pressure sensor
must be threaded through the 20 mm conduit hole on the rear of the electronics
housing.
Plug the connector on to the pin header (as indicted in Figure 20) making sure that the
blanking pin is aligned correctly with the missing pin on the plug.
Refit the end cap ensuring that no wires are crushed and tighten the cable gland to
13 N m (9.58 lbf ft) to ensure an IP65 seal.
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IM-P192-02 MI Issue 1
EIA 232 (RS 232)
Communication port
(RJ11 socket)
Superheat pressure sensor
pin header connection
Pulse
+ -
Loop
- +
1
2
Remote NPN input
(maximum 28 V)
Power
M750 display unit
with 4-20 mA active
input (supplying
current loop)
R
0 Volts
N
3
4
-
5
+
L
230 V
50 Hz
Fuse 1A
Or R  10 k
Power
0 Volts
+
9 - 28 Vdc
-
R
Loop powered
4-20 mA
display unit or
chart recorder
Remote PNP input
(maximum 28 V)
Fig. 20 Wiring diagram
IM-P192-02 MI Issue 1
25
Power supply requirements
A nominal 24 Vdc is needed to power the flowmeter. However, the TVA flowmeter will operate
correctly as long as the power supply is in the range shown in Figure 20. A single, stand-alone,
supply may be capable of powering several transmitters. It can be mounted in a control room
or in the field, but cannot be on the same loop. Follow the power supply manuacturer’s
recommendations with regard to mounting and environmental considerations.
The graph (Figure 21) shows the range of power supply voltages and loop resistances
over which the TVA flowmeter is capable of operating. The loop resistance includes all the
wiring.
V (volts)
TVA flowmeter
operating range
Fig. 21
V = 0.022R + 6
9 V  V  28 V
R (ohms)
Cable length
Generally the maximum cable length between the TVA flowmeter and the power supply
is 300 m (984 ft).
However the actual cable length is governed by the number of network devices, the total
resistance of the network and the cable capacitance.
Suggested cable type: for both loop and pulse should be shielded twisted pairs, each core,
seven stranded wire with cross sectional area of 0.5 mm².
EMC cable glands suitable for M20 x 1.5 to EN 50262 / IP68 are recommended.
The cable gland / body torque setting is 13 N m (9.58 lbf ft).
The gland nut torque setting (with cable fitted) is 12 N m (8.85 lbf ft).
26
IM-P192-02 MI Issue 1
4. Commissioning
After all mechanical and electrical work
has been completed, the following
commissioning instructions should be
followed.
The TVA flowmeter should
be commissioned with the
flow through the unit
isolated.
Note: The TVA flowmeter is
factory set to display data in
metric units. To commission
the TVA to diplay imperial units
see Section 4.4.2, page 34.
LCD
display
5 button
keypad
Mounting screws
Fig. 22 TVA flowmeter display unit
All commissioning is carried out through the display unit installed behind the front end cap
of the TVA flowmeter enclosure. The display unit consists of a small LCD display and a
5 button key pad.
As all the commissioning settings are stored in a non-volatile memory, it is possible to connect
a 9 V PP3 battery to the TVA flowmeter's 4 - 20 mA loop power supply and commission the
unit uninstalled. However, if using a TVA for a superheat application (with pressure sensor),
the sensor must be connected before powering up the flowmeter. Otherwise the pressure
channel calibration will be affected. The TVA flowmeter should still be zeroed in-line (see
Section 4.5.3) and its operation checked. An M750 display unit can be used to provide a
remote display function if required, utilising the linear output.
Rotating the display
The display can be rotated through 180° to enable ease of commissioning. To rotate the
display disconnect the power supply, remove the mounting screws on the display unit, carefully remove the display unit and rotate. Carefully replace the display unit and replace mounting screws. Do not force the display unit into position. Reconnect the power supply. Note 1 - Electrostatic discharge (ESD) procedures should be followed while rotating the display.
Note 2 - DO NOT remove the 10 way connector from the display.
4.1 Run mode
Normally, the TVA flowmeter will operate in the run mode, displaying the total flow, flow, power,
pressure or temperature of the fluid passing through the pipeline.
After initial power up, the TVA flowmeter will automatically enter the run mode and all
commissioning menus can be accessed from this mode. (See Section 4.2, Commissioning
mode, for details on how to commission).
In the run mode the fluid data is displayed on
several screens which can be accessed by
pressing the up or down keys. The display shows
Arrow
a numeric value and an arrow indicating the reading
total
power
flow
pres
type, i.e. total flow, flow, power, pressure or
temperature. All units (except °C) are implied with
imperial or metric units being indicated by another
arrow. The value of total flow is shown in two parts.
The first five digits of the total flow will be displayed
and after 10 seconds the following five digits will
imp
be displayed. To access the first five digits of total
temp
flow again it will be necessary to scroll up or down
Fig. 23
and return to the total flow display.
IM-P192-02 MI Issue 1
27
4.1.1 Run mode data sequence
Total High
kg or lb
Total Low
kg or lb
Flow
POWER
Power kW or kBtu /h.
Pressure
Pressure bar g or psi g, depending if
metric or imperial units are selected.
Temp. °C
Temperature °C or °F.
The following chart indicates the run mode data display sequence.
Depending on the configuration, the flow units will be:
Units
Metric
Imperial
Steam
kg, kg / h, kW, bar g, °C
lb, lb / h, kBtu / h, psi g, °F
The TVA flowmeter is factory set to display steam data in metric units and pressing the up or
down keys will scroll through the following data.
total
flow
power
pres
Total flow
temp
total
imp
flow
power
pres
total
flow
power
pres
Temperature
Flow
temp
total
imp
flow
temp
power
pres
total
imp
flow
Pressure
Power
Fig. 24
28
power
pres
temp
imp
temp
imp
IM-P192-02 MI Issue 1
4.1.2 Error display messages
Any errors that occur will be displayed in the run mode. The errors will alternate with the normal
run mode display and will be prioritised. The errors will be latched and can only be cancelled by
pressing the 'OK' button. Once the error message has been cancelled the display will show the
next (if any) error.
Any continuous error will reinstate itself 2 seconds after it has been cancelled, and will be indicated
by a flashing exclamation mark (!).
Certain errors will also cause the 4-20 mA alarm signal to be initiated.
The error messages are displayed over two screens and are:
POWER
OUt
= Power interrupted.
No signal from sensor.
NO
= (This can also activate
SIGNL
the 4-20 mA alarm).
Signal from sensor constant.
SENSR = (This can also activate
CONSt
the 4-20 mA alarm).
HIGH
FLOW
SUb
SAt
IM-P192-02 MI Issue 1
= Flow above the maximum.
= Line conditions have changed from
superheat to saturation (only when
pressure sensor enabled).
29
4.2 Commissioning mode
The commissioning mode is used to zero the flowmeter, re-range, enable the pressure sensor
(for superheat applications), set and test the outputs and change the pass code.
All data entry is performed via a menu and sub menu configuration with the key pad buttons
used for navigation, i.e. to go deeper into the menu the right hand key is pressed, to scroll up
and down the menu the up and down keys are pressed and to exit from a sub-menu the left key is
pressed. Any data is entered using the OK button. The previously entered selection will
flash. After a period of five minutes without any keys being pressed the TVA flowmeter will
automatically default to the run mode.
For a full commissioning flow chart see Section 4.3.
To enter the commissioning mode press and hold down the 'OK' key for 3 seconds. The display
then shows:
ENtER
PASS
Followed by:
7452
The leading digit will flash indicating that this is the position of the cursor.
The default factory set pass code is 7452. (This can be changed from within the commissioning
mode). The pass code can be entered by using the up and down keys to increment the flashing
value and the left and right keys to move the cursor. Pressing 'OK' will enter the pass code.
If an incorrect pass code is used the display will automatically return to the run mode.
After the correct pass code is entered the display shows:
bASIC
dAtA
30
IM-P192-02 MI Issue 1
To exit from the commissioning mode at any stage, continually pressing the left key will return
to the run mode.
Pressing the up and down buttons scrolls through the various first level menus.
Pressing the right arrow button enters a particular sub-menu.
ENtER
PASS
8888
bASIC
dAtA
MEtER
OUt
PUts
PRES
SENSR
tESt
ALARM
SWVER
SEt
PASS
IM-P192-02 MI Issue 1
31
4.3 TVA flowmeter commissioning flow chart
Software
version number
Normal run mode
display sequence
VER x.x
Total
high
ENtER
PASS
Total
low
kg or lb
(kWh or kBtu)
Flow
kg /h or lb / h
Power
kW or kBtu /h
(test
display)
Power on sequence; turn
on all segments, then
show the software version
no.
Default = 8888
but user settable.
Configuration
sub-menus
8888
bASIC
dAtA
MEtER
Pressure
bARG or PSIG, depending if metric or
imperial units are selected.
Temp. °C
°C or °F
OUt
PUtS
Error Messages
These alternate with the normal run mode display.
They will be prioritised and will be latched when
they occur.
Pressing the 'OK' button will cancel the displayed
alarm and allow the next one to be viewed.
A continuous alarm will re-occur on the display
2 seconds after it has been cancelled.
Power
interrupted
POWER
OUt
No
signal from
sensor
NO
SIGNL
The 4-20 mA
alarm can also
be activated
Signal
from sensor
constant
SENSR
CONST
The 4-20 mA
alarm can also
be activated
Flow
above
maximum
HIGH
FLOW
Shows when
flow exceeds
maximum
Temp
below
saturation
SUb
SAt
HIGH
Line temperature
drops below
steam saturation
temperature
xxxx
SEt
PASS
xxxx
SWVER
O/P
ALARM
ALARM
LOW
OFF
ON
POWER
ALARM
PRES
SENSR
OFF
ON
CONSt
ALARM
OFF
XX
dELAy
yES
NO
32
SAt
ALARM
tESt
IM-P192-02 MI Issue 1
dRy
xxx%
MEt
UNItS
MASS
tOtAL
IMP
ENERGy
AtMOS
PRES
xxx.xx
dIR
HORIZ
dOWN
UP
CLEAR tOtAL
S/N
xxxxx
ZERO MEtER
4-20 mA
PULSE
SORCE
yES
SORCE
POWER
tOtAL
NO
SEt4 mA
ENRGy
NUM /
PULSE
xxxxx
SEt20 mA
xxxxx
CHECK
4 mA
xxxmS
OP = 4 mA
Connect a DVM
and use the up
and down keys to
set 4 or 20 mA.
Must not
exceed 4 pulses
per second.
bAUD
CHECK
20 mA
1200
tyPE
xxxxx
in kg /h or lb /h,
kW or kBtu /h.
in kg or lbs,
MJ or kBtu.
PULSE
WIDTH
COMMS
FLOW
ASCII
9600
MOdbuS
Add
OP = 20 mA
XXX
Press OK to select
yES
0CAL
XXXXX
NO
25CAL
XXXXX
SH MARGN
PRES
ALARM
ON
yES
LIMIt
XXX
NO
ALARM
OFF
OFF
ON
dELAy
dISP
Display
test
4-20 mA
OUt
xxx.xxmA
PULSE
OUt
ON
XXX
CANCL
IM-P192-02 MI Issue 1
OFF
33
4.4 bASIC DAtA Sub menu
bASIC
dAtA
dRy
xxx%
MEt
UNItS
MASS
tOtAL
IMP
ENERGy
AtMOS
PRES
xxx.xx
4.4.1dRy
Pressing the right key will display the dryness fraction. This is the dryness fraction of the
saturated steam being measured. This can then be edited to suit the application. Press the 'OK'
button to confirm the selection.
After the dryness fraction is entered the display will automatically step to the next sub menu
and show 'UNItS'
4.4.2UNItS
The units displayed and transmitted can be selected between metric (MEt), and imperial (IMP). A summary of the units is detailed in the Table below.
Units
Metric
Imperial
Steam
kg /h, kW, bar g, °C
lb /h, kBtu /h, psi g, °F
Select either 'MEt' or 'IMP' and press the 'OK' button to confirm.
4.4.3 CLEAR tOtAL
This function is used to clear the total by pressing and holding the 'OK' key for 3 seconds.
Note: The total is backed-up every 8 minutes in the TVA flowmeter's non-volatile memory.
If power is lost the TVA flowmeter could lose up to 8 minutes worth of totalised steam.
4.4.4 AtMOS PRES
This value compensates the flowrates for atmospheric pressure. It should be used if a high degree
of accuracy is required or when the TVA flowmeter is installed high above sea level.
Note: Values up to two decimal places can be entered.
If metric units are selected pressure units are bar absolute, for imperial units psi absolute.
34
IM-P192-02 MI Issue 1
4.5 MEtER Sub-menu
MEtER
This sub-menu contains information about the
flowmeter and is used to zero the flowmeter
and clear the total.
dIR
S/N
ZErO MEtER
HORIZ
xxxxx
DOWN
UP
CLEAR tOtAL
4.5.1dIR
dIR is the orientation that the TVA flowmeter is installed in. The TVA flowmeter can be
installed with horizontal flow up to a pressure of 32 bar g (464 psi g). For installations that require
vertical flow either up or down the maximum pressure must not exceed 7 bar g
(101 psi g). By selecting down or up the effect of gravity on the cone is taken into account.
Note: Upon entering the dIR sub-menu, HORIZ is always shown first. The actual direction
selected is the one which is flashing.
4.5.2S/N
This is the factory set serial number of the TVA flowmeter and is displayed by pressing
the right key.
4.5.3 ZErO MEtER
This function is used to zero the TVA flowmeter manually to compensate for any electronic
drift.
The procedure for zeroing the flowmeter is as follows:
-
-
Isolate the pipeline where the flowmeter is installed and ensure that there is no flow.
The line temperatures should be above 5°C (41°F) and below 30°C (86°F).
Press and hold the 'OK' button for three seconds.
On completion the display will step back to S /N.
If 'ZErO ErrOr' is displayed, check to ensure that the line is isolated with no flow.
If 'tEMP ErrOr' is displayed the line temperature is below 5°C (41°F). Allow the temperature
to move above 5°C (41°F) and re-zero. Note: The flowmeter should ideally be zeroed
annually after 12 months service.
4.5.4 CLEAR tOtAL
This function is used to clear the total by pressing and holding the OK key for 3 seconds.
Note: The total is backed-up every 8 minutes in the TVA flowmeter's non-volatile memory.
If power is lost the TVA flowmeter could lose up to 8 minutes worth of totalised steam.
IM-P192-02 MI Issue 1
35
4.6 OutPutS Sub-menu
This sub-menu allows both the 4-20 mA and pulsed
outputs of the flowmeter to be configured.
OUt
PUtS
4-20 mA
PULSE
4.6.1 4-20 mA Output sub-menu
OUt
PUtS
4-20 mA
SORCE
FLOW
POWER
The 4-20 mA sub-menu allows
re-ranging and re-calibrating of
the 4-20 mA output.
SEt4 mA
XXXX
SEt20 mA
XXXX
CHECK
4 mA
OP = 4 mA
CHECK
20 mA
OP = 20 mA
4.6.2SORCE
This changes the source data for the 4-20 mA between flow and power.
4.6.3 SEt4 mA
This sets the value for the flowrate or power, which is equivalent to 4 mA. The minimum value
that can be set as 4 mA is 0 and the maximum is the 20 mA equivalent value less one.
4.6.4 SEt20 mA
This sets the value for the flowrate or power, which is equivalent to 20 mA. The minimum value
that can be set as 20 mA is the 4 mA equivalent value plus one and the maximum is the meters
rated maximum at 32 bar g. The 20 mA value must always be a minimum of one greater than
the 4 mA value.
4.6.5 CHECK 4 mA
This allows the 4 mA value to be re-calibrated. A digital volt meter / multimeter should
be connected in series with the 4-20 mA output. Pressing the right arrow button will display
OP = 4 mA and the TVA flowmeter will output a steady 4 mA. If the multimeter does not
read 4 mA the up and down arrow buttons can be pressed to alter this current until
4 mA exactly is indicated. Pressing the 'OK' button confirms the setting.
4.6.6 CHECK 20 mA
This allows the 20 mA value to be re-calibrated. A digital volt meter/multimeter should
be connected in series with the 4-20 mA output. Pressing the right arrow button will display
OP = 20 mA and the TVA flowmeter will output a steady 20 mA. If the multimeter does not
read 20 mA the up and down arrow buttons can be pressed to alter this current until
20 mA exactly is indicated. Pressing the 'OK' button confirms the setting.
36
IM-P192-02 MI Issue 1
4.6.7 Pulse Output
This sub-menu allows the pulsed output to be configured.
PULSE
yES
SORCE
NO
tOtAL
ENRGy
NUM /
PULSE
xxxxx
PULSE
WIDTH
xxxmS
4.6.8 PULSE
This selects whether the pulsed output is to be used or disabled.
4.6.9 SORCE
This selects the source data for the pulsed output. The source data can be either unit mass per
pulse (tOtAL) or unit energy per pulse (ENRGy).
4.6.10 NUM / PULSE
This allows the total mass, or energy, which is equivalent to one pulse to be configured.
Units are dependent on the UNIt setting. Metric units will be kg for total or MJ for energy,
imperial units will be lb for total or kBtu for energy.
4.6.11 PULSE WIDTH
This allows the width of the pulse to be set. The width can be set in 0.01 second increments from
0.02 seconds to a maximum of 0.2 seconds.
4.6.12 COMMS
This allows the connection to other communications protocols.
COMMS
bAUD
tyPE
1200
ASCII
9600
MOdbuS
Add
xxx
Press OK to select
4.6.13 bAUD
This allows the communication speed to be set to either 1200 or 9600. This must match the rate
set within the device it is communicating to.
4.6.14 tyPE
This gives the choice to select either ASCII or Modbus protocols.
4.6.15 Add
If you have selected Modbus communications you must add an address. This is a three digit
number between 001 - 255. Again this must match the address that the device that you are
communcating to is set to.
IM-P192-02 MI Issue 1
37
4.7 PRES SENSR sub-menu
PRES
SENSR
yES
0CAL
XXXXX
NO
25CAL
XXXXX
SH MARGN
PRES
ALARM
ON
yES
LIMIt
XXX
NO
ALARM
OFF
OFF
ON
dELAy
XXX
Selecting 'YES' at the PRES SENSR menu will enable the pressure sensor option.
4.7.1 0CAL
When the pressure sensor has been enabled, the 0CAL menu will be displayed. Pressing
the right arrow key (>) will display the 0CAL bits values.
The calibration certificate supplied with every pressure sensor kit lists the 0CAL and
25CAL bits values that are required to be entered.
4.7.2 25CAL
Pressing the down arrow key (v) will display the 25CAL bits values. The calibration certificate
supplied with every pressure sensor kit lists the 25CAL bits values that are required to be
entered into this menu.
When the bits values for the 25CAL have been entered press the OK button to confirm.
This will automatically display the SH MARGN menu.
4.7.3 SH MARGN
The SH MARGN menu enables the configuration of the superheat alarm, the superheat
limit (in degrees C) and delay before the alarm is triggered.
LIMIt
Number of degrees of superheat have dropped before alarm is triggered.
ALARM
Can be set to ON or OFF.
dELAy
The alarm in seconds before the alarm is triggered.
4.7.4 PRES ALARM
In the event the alarm is triggered 'LOWS-HT' will be displayed. The PRES ALARM is
activated in the event that the pressure has exceeded 30 bar g. In this event 'OVER PRES'
will be displayed.
4.7.5WAIT
On exiting the 'PRES SENSR' menu the wait command will be displayed. At this point the
software is zeroing the pressure channel. This will return to normal after approximately
5 seconds.
38
IM-P192-02 MI Issue 1
4.8 tESt sub-menu
The tESt sub-menu allows access to the TVA flowmeter's diagnostic tools. From here the
display, 4 -20 mA and pulse outputs can be tested.
tESt
dISP
4-20 mA
OUt
xxx.xxmA
PULSE
OUt
ON
CANCL
OFF
4.8.1dISP
This allows the display to be tested. Pressing the right button will cause all the segments
on the display to be turned on. Pressing the left button cancels the test and steps to the
next stage.
4.8.2 4-20 mA Out
This allows the 4-20 mA output to be tested. By editing the value and pressing the 'OK'
button the output can be set to the selected output. This current will continue to be
transmitted for five minutes unless the cancel option is chosen.
4.8.3 PULSE OUt
This allows the pulsed output to be tested. By selecting 'ON' or 'OFF' the desired test state of
the pulsed output can be selected. Once the 'OK' button is pressed the pulsed output
will remain in the selected state for five minutes or until the cancel option is chosen.
4.8.4CANCEL
This allows the 4-20 mA output and pulsed output test signal selected above to be
cancelled before the five minutes duration has expired.
IM-P192-02 MI Issue 1
39
4.9
ALARM sub-menu
This sub-menu gives access to setting the action that is required on the 4-20 mA output
when an error is detected by the TVA flowmeter electronics. It also gives access to the
power alarm function.
HIGH
O/P
ALARM
ALARM
POWER
ALARM
ON
LOW
OFF
OFF
ON
CONSt
ALARM
OFF
XX
dELAy
yES
SAt
ALARM
NO
4.9.1 O / P ALARM
If the self-diagnostic electronics determine that the sensor output has been
output to 22 mA.
HIGHconstant for a period of time, or is not giving out a signal, it will set the 4 - 20 mA
If the self-diagnostic electronics determine that the sensor output has been
output to 3.8 mA.
LOW constant for a period of time, or is not giving out a signal, it will set the 4 - 20 mA
OFF This disables the 4-20 mA alarm function.
4.9.2 POWER ALARM
OFF This disables the power alarm function.
ON
40
This enables the power alarm function.
IM-P192-02 MI Issue 1
4.9.3 CONSt ALARM
This allows the constant flow alarm to be turned off.
The constant alarm is switched to on by the default factory setting. It detects if the flow has
been constant for long periods when at pressure, which may indicate a stuck cone due to
debris. If the system that the TVA is fitted to, has long periods where there is zero flow, but
the line is kept at a constant pressure, it is advisable to turn the alarm off to avoid unwanted
alarm messages.
ON
This enables the saturated steam alarm.
OFF
This disables the saturated steam alarm.
dELAy
This enables the time duration before alarm is displayed.
4.9.4 SAt ALARM
yES
Enables the Sub Saturation Alarm.
NO
Disables the Sub Saturation Alarm.
dELAy
This sets the time duration before alarm is displayed. Can be zero.
This allows the Sub Saturation Alarm to be enabled or disabled.
The Sub Saturation alarm is switched off by default. If set it will alarm if the steam temperature
drops 2°C below saturation temperature.
4.10SWVER
This allows the software version to be viewed.
SWVER
xxxx
SEt
PASS
xxxx
4.11 SEt PASS
This allows the default pass code to be changed
to a user defined value.
It is important that if the default pass code is
changed that the new value is noted and kept safe.
The new pass code can be recorded on the Table
in Section 9, page 50.
IM-P192-02 MI Issue 1
41
4.12 TVA communications
4.12.1 TVA UART set-up
The TVA flowmeter has an EIA 232C compatible communications link and supports two
protocols: a simple Line Feed [LF] terminated ASCII protocol and a subset of Modbus/RTU.
This enables users to easily interrogate the TVA flowmeter for steam data using either a dumb
terminal or a P.C. loaded with a simple terminal emulation program or a standard Modbus
Master / Client application. The connection length is limited to 15 metres and must be in the
same building / area as the TVA flowmeter.
The TVA’s communication set up should be as follows:
TVA ASCII set-up
TVA Modbus set-up
Baud rate
1200 or 9600
Baud rate
Data bits
7
Data bits
8
Stop bits
one
Stop bits
one
Parity
none
Parity
none
Echo
off
Echo
off
1200 or 9600
Response time:
The TVA will start responding within 500 msec. The actual time to fully receive a response
from the TVA is baud rate dependent, for example a Modbus poll of 12 registers @1200 baud
rate could take ((5 + 24) bytes x ~10 ms / byte) + 500 ms ≈ 800 ms to complete.
The polling frequency can be faster if the polling algorithm is set to poll immediately after
receiving a valid response to a poll.
4.12.2 Using the EIA 232C communications
It is assumed that:
- The electrical wiring for the EIA 232C communications has been carried out in accordance
with the EIA 232C standard. Please note the TVA EIA 232C connection requires a connector
RJ11 linked to a 9 way D-type adaptor. Figure 25 illustrates the TVA flowmeter's
RJ11 socket from the front.
The table below lists the RJ11 socket's pin connections. The signals are named from the PC (or data terminal) end.
RJ11 pin
9-way D-type
1
Signal
Not used
2
4
DTR
3
5
GND
4
2
RX
5
3
TX
6
8
CTS
654321
Pin numbers
Fig. 25 RJ11 socket
42
IM-P192-02 MI Issue 1
- The communications protocol has been set up on the communicating device as described
earlier in this Section. The following is a Table of operating codes in ASCII characters:-
ASCII communications
Please note that all the following commands are case sensitive…
User transmits
TVA responds (metric)
TVA responds (imperial)
AB[LF]
Pressure in bar g [LF]
Pressure in psi g
AC[LF]
Line Temperature in °C [LF]
Line temperature in °F
AH[LF]
Energy total in kWh [LF]
Energy total in kBtu
AP[LF]
Power in kW [LF]
Power in kBtu / h
AR[LF]
Flow rate in kg / h [LF]
Flow rate in lb / h
AT[LF]
Total in kg [LF]
Total in lb
4.13
After installation or maintenance ensure that the system is fully functioning.
Carry out tests on any alarms or protective devices.
IM-P192-02 MI Issue 1
43
4.14 Modbus communications
The TVA flowmeter has Modbus communications, in addition to the ASCII Modbus comms
that are available through the TVA RS232 port. An RS485 to RS232 converter is required,
or alternatively, an Ethernet to RS232 converter, both of which are widely available.
Modbus comms protocol
Format: Request frame
Address
Function code
Start address
Quantity of registers
Error check (CRC)
Total
1 byte
1 byte
2 bytes
2 bytes
2 bytes
8 bytes
Format: Response frame (normal)
Address
1 byte
Function code
1 byte
Byte count
1 byte
Register data
2 x Quantity of registers, MSB first, low register address first
Error check (CRC)
2 bytes
Total
5+ (2 x Quantity of registers) bytes
Format: Response frame (error)
Address
1 byte
Error code
1 byte (error code = function code plus 0x80)
Exception code
1 byte (01 or 02 see below)
Error check (CRC)
2 bytes
Total
5 bytes
Note: Only ‘Read holding registers’ (function code ‘03’) is currently supported
4.14.1 ModBus request frame structure example.
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
Device
address
Function
code
Register
start
address
(MSB)
Register
start
address
(LSB)
Register
quantity
(MSB)
Register
quantity
(LSB)
CRC
(LSB)
CRC
(MSB)
x
(3)
(0)
(0)
(0)
(12)
x
x
The above frame will poll all Modbus registers from Total low 16-bits up to and including
Software Version.
44
IM-P192-02 MI Issue 1
Register
number
Modbus
address
Parameter
Received
data
scale
Units
40001
0
Total low 16 bits
x1
Kg
40002
40003
40004
40005
1
2
3
4
x1
x1
x100
x10
Kg
Kg/h
BarG
°C
40006
5
x10
L/hour
40007
6
x1
kW
40008
7
x1
kWh
40009
8
x1
kWh
40010
40011
9
10
Total high 16 bits
Flow
Pressure
Temperature
Water equivalent
flowrate
Power
Energy low
16 bits
Energy high
16 bits
Alarm status
SxS device ID
40012
11
Software version
-
40021
20
Total low 16 bits
x1
40022
40023
40024
40025
21
22
23
24
x1
x1
x100
x10
40026
25
x10
Lbs/hour
40027
26
x1
KBTU/h
40028
27
x1
kBTU
40029
28
Total high 16 bits
Flow
Pressure
Temperature
Water equivalent
flowrate
Power
Energy low
16 bits
Energy high
16 bits
(bit-fields) Look table below
TVA = 0
200 is sw ver 2.00, 201
is sw ver 2.01 etc
Total = (Total high x
Lbs
65536) + Total low *
Lbs
Lbs/h
PSIg
°F
x1
kBTU
-
Notes
Total = (Total high x
65536) + Total low *
Energy = (Energy high x
65536) + Energy low *
Energy = (Energy high x
65536) + Energy low *
Note Modbus protocol requires that Modbus addresses start at offset 0, not 1. Register
addresses start from 1 in description but 0 in binary. Most parameters are 16 bits and few
parameters are 32 bits. Modbus registers are 16 bits, i.e. 1 device parameter needs 1x and 2x
Modbus register(s) respectively. As a general note on Modbus, register types and reference
register number ranges are implemented as follows:
0x = Coil = 00001 - 09999
1x = Disc rete input = 10001 - 19999
3x = I n p u t r e g i s te r = 30001 - 39999
4x = Holding register = 40001 - 49999
IM-P192-02 MI Issue 1
* Multiply by the inverse 'Received Data
Scale' to extract data in relevant units,
i.e. divide polled 'Temperature' by 10
to get the value in °C… Tip: use real
(float) type to retain 2-decimal-point
accuracy.
45
4.14.2 Alarm status register bit-fields:
Bit 1
Bit 0
State
Alarm code
0
0
Superheat
0x0000
0
1
Not applicable
Not applicable
1
0
Saturated
0x0002
1
1
Sub-saturated
0x0003
Bit
Set (1)
Cleared (0)
Bit 2 (0x0004)
Pressure alarm is active
(too high or too low)
Pressure alarm is idle
Bit 3 (0x0008)
Superheat margin active
Superheat margin idle
Bit 4 (0x0010)
Hi flow alarm is active
Hi flow alarm is idle
Bit 5 (0x0020)
Sensor constant alarm is active
Sensor constant alarm is idle
Bit 6 (0x0040)
No signal from sensor alarm is
active
No signal from sensor alarm is
idle
Bit 7 (0x0080)
Power failed (has been turned off
and on) alarm is active
Power failed alarm is idle
Bit 8 (0x0100)
Hi flow alarm has latched
-
Bit 9 (0x0200)
Sensor constant alarm has latched
-
Bit 10 (0x0400)
No signal from sensor alarm is
latched
-
Bit 11 (0x0800)
Power failed alarm has latched
nothing
Bit 12 (0x1000)
Low superheat (Low S-HT) alarm
-
Bit 13 (0x2000)
Over pressure alarm (OVEr PRES)
-
A maximum of 12 Modbus registers can be polled together at the same frame. It has to be
noted that only a poll with a valid start address and quantity that falls within the supported
register range will produce a normal frame response. If you ask for a frame with start address
outside this range or a frame that the start address + quantity falls outside this range, the
TVA will reply with an 'illegal data address' error message. If the function code is incorrect,
it will reply with an 'illegal function' error message.
If a message is received with the wrong CRC, it will be ignored. The TVA response time is
not instant (look below) so wait for it to reply before asking for more data, otherwise it will
ignore new requests.
As the TVA is a loop powered instrument, it needs CTS and / or DTR to be wired into it so
that it can use these to power its communications interface.
4.14.3 Response time:
The TVA will start responding within 500 msec. The actual time to fully receive a response
from the TVA is baud rate dependent, for example a Modbus poll of 12 registers @1200 baud
rate could take ((5 + 24) bytes x ~10 ms / byte) + 500 ms ≈ 800 ms to complete.
The polling frequency can be faster if the polling algorithm is set to poll immediately after
receiving a valid response to a poll.
46
IM-P192-02 MI Issue 1
5. Operation
The TVA flowmeter operates by measuring the strain produced on a moving cone by an
instantaneous flowrate. This strain is then converted into a density compensated mass flowrate
and is transmitted via a single loop powered 4 - 20 mA output and pulsed output. The unique
design of the TVA flowmeter produces the high turndowns and high accuracy required in process
applications.
6. Maintenance
The TVA flowmeter should be zeroed using the zero meter sub-menu at least once a year.
This will remove any electronic long term drift that may occur. Frequency of re-calibration
depends upon the service conditions experienced by the meter and the application.
Re-calibration frequency can be typically between 2 and 5 years.
Replacement of the TVA flowmeter display electronics
To replace the electronics:
-
-
-
-
-
-
Disconnect the power supply.
Remove the front housing.
Remove the mounting screws on the display unit and carefully remove the electronics.
Carefully unplug the ribbon cable.
Reconnect the ribbon cable to the new electronics and carefully replace.
Replace the mounting screws and reconnect the power supply.
Note: Electrostatic discharge (ESD) procedures should be followed while installing the new
electronics.
Do not force the electronics / display unit into position.
7. Spare parts
Spare electronics for the TVA flowmeter are available from Spirax Sarco and consist of:
-
TVA flowmeter replacement display and electronics with front housing.
It is important that the serial number of the TVA flowmeter is given at the time of ordering.
Example: 1 off Spirax Sarco display and electronics panel for a DN100 TVA flowmeter having
the following Serial number D______ . This can be found on the product label on the stem.
Please note that a conversion kit to upgrade any TVA for use with superheated steam is also
available. The existing serial number of the TVA will be required at the time of order placement.
IM-P192-02 MI Issue 1
47
8. Fault finding
Many faults which occur on commissioning are found to be due to incorrect wiring or setting up,
therefore it is recommended that a thorough check is carried out should there be a problem.
The TVA flowmeter display has in-built diagnostic features and will indicate a number of
errors on the display and via the 4-20 mA output.
The errors will alternate with the normal run mode display and will be shown according to priority.
The errors will be latched and can only be cancelled by pressing the 'OK' button. Once the error
message has been cancelled the display will show the next (if any) error.
Any continuous error will re-instate itself 2 seconds after it has been cancelled, and will be
indicated by a flashing exclamation mark (!).
Symptom
Display is blank
Possible cause
dc voltage is not within
the range of 9-28 Vdc.
Action
Check power supply /current
connections. See Section 3.3.
Supply connected with
reverse polarity.
Change polarity.
Electronics faulty.
Refer to:
Spirax-Sarco Limited
Display shows:
Insufficient supply voltage. Check supply voltage is between NO SIGNL
9 and 28 Vdc.
Current loop resistance
is greater than Rmax.
Check current loop resistance
and reduce if necessary.
Electronics faulty.
Check current output electronics
(refer to Sections 4.6, 4.7 and 4.8).
Refer to:
Spirax-Sarco Limited
Display shows:
Power supply interrupted.
POWER Out
Ensure power supply is secure and
cancel error using the OK key.
Totals transmitted may not be valid.
Display shows:
SENSR CONST
Cone jammed.
Remove unit from pipeline and
check cone movement.
Electronics Faulty.
Check current output electronics
(refer to Sections 4.6, 4.7 and 4.8).
Refer to:
Spirax-Sarco Limited
Display shows:
Meter undersized.
HIGH FLOW
Check sizing and replace
if necessary.
Constant 3.8 mA
Check display for errors
and rectify as above.
Error signal set to Low.
Check current output electronics
(refer to Sections 4.6, 4.7 and 4.8).
Constant 22 mA
Check display for errors
and rectify as above.
Error signal set to High.
48
Check current output electronics
(refer to Sections 4.6, 4.7 and 4.8).
IM-P192-02 MI Issue 1
Symptom
Possible cause
Action
Flow indicated Flowmeter not properly
The axis of the flowmeter bore
responds to changes in centred in the pipeline.
should be aligned with that of the
actual flow but value pipe.
indicated does not
Gaskets at the flowmeter
See Section 3, Figures 16, 17 and 18
correspond to actual protrude
into
the
pipe
bore.
for proper installation of gaskets.
flowrate
Irregularities on the surface Pipe bore should be
of the pipe bore.
free of irregularities.
Signal falsified due to
bi-phase medium.
Bi-phase media are not permitted.
Use a separator for wet steam
applications to remove moisture
droplets from the steam.
See Section 3 for correct lengths
of upstream and downstream pipes.
Insufficient upstream /
downstream pipe lengths.
Flow direction reversed.
Check flow direction arrow
on primary.
Pulse output is
Pulse output incorrectly set. Check programming of pulse output,
incorrect
Section 4.6.7.
Pulse width incorrectly set. Check maximum pulse width of
counter electronics.
Pulse output is overloaded. Check load ratings.
Pulse output electronics
faulty.
TVA produces largeUpstream /downstream amount of noise
installation lengths (banging and clattering)incorrect.
Test pulse output.
If faulty replace unit.
Re-install following the installation
guidelines (Section 3).
Non zero flow indicated Unit not zeroed at Zero unit.
when
no actual flow is commissioning.
in the pipe.
4 mA output not calibrated. Calibrate 4 mA output
(Section 4.6.5).
4 mA retransmission set to Reset 4 mA.
a value higher than zero.
Interference.
IM-P192-02 MI Issue 1
Check earthing.
49
9. Settings table
This Table shows all changeable options, and enables records to be made of any changes
made to the pass code or other settings. It provides a convenient reference should future
changes be required.
Sub-menu Changeable settings
Dryness fraction
Factory settings
Customer
settings
Further
changes
1.0
Units
Metric
Basic data
Nominal pressure
Atmospheric pressure
4-20 mA
Source data
Flow
4 mA setting
0
Outputs
20 mA setting
Pulse
Source data
Number of pulses
Pulse width
1.01 bar a
Flowmeter
maximum
@ 32 bar g
ON
Total
1 per kg
50 mS
Error
High
Pass code
7452
50
IM-P192-02 MI Issue 1
IM-P192-02 MI Issue 1
51
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IM-P192-02 MI Issue 1
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