K-Patents SeedMaster 2 User Manual
INSTRUCTION MANUAL FOR THE
SeedMaster 2
Crystallization Transmitter and Automatic Seeding
Device
Document/Revision No. SeedMaster 2: Rev. 1/06 Effective: January 16, 2014.
PROCESS CONTROL KFT. PROFICON Industrial Controls Ltd.
Postal address: Postal address:
1091 BUDAPEST 1025 BUDAPEST
Haller u. 88. Mandula u. 24.
HUNGARY HUNGARY
E-mail: info@processcontrol.hu E-mail: LajosRozsa@mail.datanet.hu
www.processcontrol.hu
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CONTENTS
1
INTRODUCTION ......................................................................................................................................... 4
2 SUGAR CRYSTALLIZATION IN BRIEF ................................................................................................ 6
2.1 THE LAST STEP: CRYSTALLIZATION .......................................................................................................... 6
2.2 SUPERSATURATION: THE DRIVING FORCE OF CRYSTALLIZATION .............................................................. 6
2.3 SEEDING METHODS .................................................................................................................................. 6
2.4 CRYSTAL CONTENT .................................................................................................................................. 9
2.5 PRODUCT QUALITY AND SUPERSATURATION ............................................................................................ 9
2.6 COST OF PRODUCTION AND THE MAJOR PARAMETERS ............................................................................ 10
2.7 COMMON INSTRUMENTS IN USE FOR CRYSTALLIZATION CONTROL ......................................................... 11
2.8 MOUNTING THE K-PATENTS REFRACTOMETER ................................................................................... 12
3 THE SEEDMASTER 2 CRYSTALLIZATION TR ANSMITTER AND SEEDING DEVICE........... 14
3.1 SEEDMASTER 2 DESCRIPTION ................................................................................................................ 14
3.2 SEEDMASTER 2: A FRON T-END DEVICE .................................................................................................. 14
3.3 PRINCIPLE OF OPERATION ...................................................................................................................... 15
3.4 CALCULATED DATA ............................................................................................................................... 16
3.5 ON-LINE DATA INPUTS ........................................................................................................................... 17
3.5.1 Receiving syrup concentration data from the K-PATENTS refractometer(s) ...................................... 17
3.5.2 Receiving temperature data ................................................................................................................. 17
3.5.3 Selecting the “THIRD INPUT” transmitter ......................................................................................... 18
3.5.4 Using laboratory data instead of “THIRD INPUT” ............................................................................ 18
3.5.5 Optional data input .............................................................................................................................. 18
3.6 DIGITAL INPUTS ..................................................................................................................................... 18
3.6.1 “STRIKE ACTIVE” input DIN1 ........................................................................................................... 18
3.6.2 “SEEDED” input DIN2 ....................................................................................................................... 19
3.6.3 “CHANGE FEED SYRUP” input DIN3 .............................................................................................. 19
3.7 DATA OUTPUTS ...................................................................................................................................... 19
3.7.1 Data available for transmission ........................................................................................................... 19
3.7.2 Standard current outputs ...................................................................................................................... 20
3.8 DIGITAL (ON / OFF) OUTPUTS ............................................................................................................... 20
3.8.1 “SEED WARNING” output DO1 ......................................................................................................... 20
3.8.2 “SEEDING” output DO2 ..................................................................................................................... 20
3.9 THE MAN-MACH IN E INTERF ACE ............................................................................................................. 20
4 TECHNICAL DATA, MOUNTING AND ELECTRIC AL CONNECTIONS ...................................... 22
4.1 SPECIFICATIONS ..................................................................................................................................... 22
4.2 ELECTRICAL CONNECTIONS ................................................................................................................... 24
4.2.1 Power supply ........................................................................................................................................ 24
4.2.2 Process inputs and output s ................................................................................................................... 25
4.2.3 Digital communication ......................................................................................................................... 25
4.2.4 I / O wirings ......................................................................................................................................... 26
4.3 CONSTRUCTION DETAILS ....................................................................................................................... 28
5 SEEDMASTER 2 FEATURES IN BRIEF ............................................................................................... 31
5.1 SEEDMASTER 2: OPERATOR STATION FEATURES ............................................................................ 31
5.1.1 CONFIGURE ....................................................................................................................................... 31
5.1.2 SET UP ................................................................................................................................................. 31
5.1.3 DISPLAY .............................................................................................................................................. 31
5.1.4 MANUAL OPERATIONS ..................................................................................................................... 31
5.2 SEEDMASTER 2: TRANSMITTER FEATURES ....................................................................................... 32
5.2.1 Analog output ....................................................................................................................................... 32
5.2.2 Digital data communication ................................................................................................................. 32
5.3 SEEDMASTER 2: SEEDING FEATURES ................................................................................................. 32
5.3.1 Seeding based on DIGITAL INPUT DIN2 ........................................................................................... 33
5.3.2 Seeding on a command from a PCS using digital communication ....................................................... 33
5.3.3 MANUAL seeding................................................................................................................................. 33
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5.3.4 AUTOMATIC seeding based on SUPERSATURATION ...................................................................... 33
5.3.5 AUTOMATIC seeding based on DENSITY .......................................................................................... 33
6
START UP AND USE ............................................................................................................................. 34
6.1 START UP ............................................................................................................................................... 34
6.2 DEFAULT SETTINGS ................................................................................................................................ 34
6.3 DEVICE CONFIGURATION ....................................................................................................................... 35
6.4 BASIC KEY OPERAT IONS ......................................................................................................................... 35
7 CONFIGURE SEEDMASTER 2 ....................................................................................................... 37
7.1 START CONFIGURATION ......................................................................................................................... 37
7.2 ORGANIZING SEEDMASTER 2 INPUT / OUTPUT TRAFFIC ........................................................................ 37
7.3 CONFIGURING THE STRIKE ACTIVE SIGNAL ....................................................................................... 41
7.4 THIRD INPUT ...................................................................................................................................... 42
7.4.1 Third input: MASSECUITE DENSITY or MASSECUITE SOLIDS CONTENT ................................... 43
7.4.2 Third input: MOTOR CONSUMPTION .............................................................................................. 45
7.4.3 Third input: CRYSTAL CONTENT (laboratory) .................................................................................. 48
7.5 SEEDING .............................................................................................................................................. 50
7.6 ACTIVE INSTRUMENT ...................................................................................................................... 51
7.7 PASSWORD ......................................................................................................................................... 51
7.8 COMMUNICATION ............................................................................................................................ 52
7.8.1 Using the serial communication (COMX) ports. .................................................................................. 52
7.8.2 Using the ETHERNET. ......................................................................................................................... 53
7.8.3 Organizing the two-way data transfer.................................................................................................. 54
8 SET UP SEEDMASTER 2 ......................................................................................................................... 55
8.1 SET UP DISPLAY .................................................................................................................................. 55
8.2 SET UP INPUTS ..................................................................................................................................... 57
8.2.1 Data types and specifications. ............................................................................................................ 527
8.2.2 Handling the use of several feed syrups with different purities............................................................ 60
8.2.3 Set up syrup parameters. ...................................................................................................................... 61
8.3 SET UP DIGITAL I / O ........................................................................................................................... 62
8.4 SET UP ANALOG OUTPUT .................................................................................................................. 64
9 MANUAL SEEDING .................................................................................................................................. 65
10 DISPLAY ............................................................................................................................................. 67
10.1 MAIN DISPLAY .............................................................................................................................. 67
10.2 TREND ............................................................................................................................................. 69
10.3 STRIKE HISTORY ........................................................................................................................... 70
10.4 STANDARD DISPLAY ................................................................................................................... 70
10.5 SYSTEM INFORMATION .............................................................................................................. 71
10.6 TEST DATA ..................................................................................................................................... 72
11 COMMUNICATION ................................................................................................................................ 77
11.1 ETHERNET COMMUNICATION ................................................................................................... 77
Data transmission using the Ethernet ........................................................................................................... 77
Cable requirements and connection ............................................................................................................ 77
Cable specification ........................................................................................................................................ 77
Connecting the Ethernet cable ...................................................................................................................... 77
Connection settings ....................................................................................................................................... 78
Testing the connection .................................................................................................................................. 78
Troubleshooting ............................................................................................................................................ 79
MODBUS TCP / IP as implemented in SeedMaster 2 .................................................................................. 79
11.2 MODBUS PROTOCOL USING ONE OF THE COMX PORTS ................................................................... 81
11.3 DATA TYPES USED IN THE MODBUS REGISTERS ............................................................................... 85
11.4 REGISTER SET .................................................................................................................................... 86
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APPENDIX 2 : CONFIGURATION DATA SHEETS……………………………………………94
12 APPENDIX 1 : PROCEDURE TO EVALUATE THE “M”, “B” AND “C” COEFFICIENTS OF
THE WIKLUND-VAVR IN ECZ SATURATION FUNCTION. ..................................................................... 90
12.1 INTRODUCING THE SOLUBILITY COEFFICIENT ............................................................................................. 90
12.2 DETERMINING THE LOCAL SYRUP PARAMETERS ................................................................................. 90
12.2.1 Sample preparation for the saturation test ......................................................................................... 90
12.2.2 Saturation test .................................................................................................................................... 91
12.2.3 Evaluation .......................................................................................................................................... 91
SUBJECT INDEX……………………………………………………………………………………………..100
1 INTRODUCTION
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1 INTRODUCTION
Sugar manufacturing dates back more than one and a half century. World sugar production in year 2000
reached 150 million tons, which probably represents the largest amount of a product produced in crystalline
form.
Due to the long history of sugar manufacturing the sugar industry is regarded as a mature one, where no
exciting new developments can be expected. It has long traditions based on the work of skilled people, who
acquired their skill in controlling the various parts of the technology often during their lifetime. However, times
are changing. The fierce competition in the industry and in the market forces even industries with long
traditions to make effective use of the advanced methods of production in order to survive.
It became evident that besides better machinery and equipment in the technology, the use of new types of
equipment and know-how is a must for the plants if they wish to be competitive.
Some of the new equipment comes in the form of
• new instruments and
• computer-based automatic contr ol syste ms,
never heard of before, but there are substantial changes in the required know-how, too. In addition to the
usual chemical- and mechanical-engineering background experience in instrumentation, automatic process
control and in the use of computers and informatics became vital. Conclusion: there are substantial changes
even in a “mature” industry.
Crystalli zation is a very important step in sugar manufacturing. Final product quality and cost of production
depend very much on its execution. For quite a long time its control was the sole responsibility of the
“artisan” pan-man, but these times are over now. Instruments to provide some objective information on the
process appeared in the plants around the middle of the 20
information on syrup concentration (correlated to supersaturation) and on massecuite density or consistency
(correlated to crystal content). None of the instruments in use today are able to serve well both of these basic
needs.
Some of the common instruments are based on the change of an electrical parameter of the massecuite
(conductivity or / and capacitance). Due to their less than satisfactory operation, the frequency of the
electrical signal used kept increasing. The first conductivity probes used signals of only a few kHz frequency.
The RF (Radio Frequency) probes use signals in the 100 MHz range, while the fairly new microwave probes
use even much higher signal frequency. It is interesting to note that the well proven method to measure liquid
concentration, that is the use of refractometers dates back well over a century, and makes use of even
higher frequency, that is the frequency of light. The modern process refractometer which is available since
the 1980-s became the most accurate and reliable workhorse in this field.
Realising the potential and importance of the modern process refractometer, original research and
development was started by PROFICON Ltd., Hungary in the second half of the 1990-s to develop new
instruments providing reliable information on the most important parameter of crystallization: supersaturation,
combined with automatic seeding. The first result of this effort was the SeedMaster optional software,
which is available with the PR-01-S type K-PATENTS process refractometers. In a new development, the
SeedMaster 2 Crystallization Transmitter And Automatic Seeding Device offers more and advanced
features. Both devices are unique, represent a completely new class of instruments and are based on
several decades of experience in carrying out mill-wide automatic control projects in several countries of the
world.
IMPORTANT NOTICE:
Realizing that SeedMaster 2 is a device not comparable to any of the common ones used in crystallization,
this manual probably discusses in more detail some special issues related to the subject, than usual. While
doing so the main effort was directed to increase the realization of the importance of supersaturation in
crystallization control, a long neglected field because of the lack of a reliable instrument capable to provide
on-line data on it. Recommendations on some issues, for example: method of seeding, the value of
supersaturation during a crystallization process are really only recommendations, and though they certainly
are in line with the latest results of research in this field, it is up to the end user how she / he wants to use the
instrument.
The manufacturer of SeedMaster 2 can not be made responsible for any type of damage that might be
caused by its use.
th
century. They were intended to provide
2 SUGAR CRYSTALLIZATION IN BRIEF
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2 SUGAR CRYSTALLIZATION IN BRIEF
2.1 The last step: crystallization
The main steps of sugar manufacturing are:
• sugar extraction (from cane or beet),
• juice purification and concentr ation , and
• crystallization.
SeedMaster 2 was designed to provide all the vital information required to control the process of sugar
crystallization on an unprecedented level. It is therefore logical to concentrate further discussions on t he
process of crystallization.
Two methods to produce sugar crystals can be distinguished:
• cooling crystallization and
• evaporative crystallization.
Most of the sugar crystallized is produced in evaporative crystallization in batch or lately in continuous
evaporative crystallizers, but the basic principles of operation are the same in both types of crystallization
methods. Traditionally the vacuum pan operating in batch mode became the major piece of machinery and
enjoys wide use all over the world.
Crystallization is a very important part of sugar manufactur ing. This is a p roc ess which has a large influence
on product quality and on the cost of production, both of which are very important when competitiveness is
at stake.
During most of its long history the control of sugar crystallization in batch pans was the undisputed authority
of the pan-men, who acquired their skill during a large number of years in practice. Working mostly without
any real instruments, they used only their eyes and fingers to keep the process under control. No wonder,
they still are being regarded as “artisans” of their profession. However, artisans can be quite different, and
quite often tend to behave rather unpredictably, which is far from being compatible with the quality- and cost-
conscious requirements of industrial mass production, so representative of our times.
Modern control of crystallization must rely on the reliable on-line measurement of the parameters which are
vital in the control of the process performed by a local operator (manual control), or by an advanced
automatic process control system (PCS).
2.2 Supersaturation: the driving force of crystallization
It is well known that crystallization can take place only in solutions which contain more solids in solution than
required to saturation. In case of sugar solutions the same mass of water can dissolve different amounts of
sugar depending on its temperature: the amount of sugar is larger, if temperature is higher. A saturated
sugar solution therefore can be supersaturated either by decreasing its temperature (cooling), or by
decreasing the mass of water (evaporation).
Supersaturation is defined as the amount of sugar dissolved divided by the amount of sugar required for
saturation in the same amount of water at the same temperature. We have real supersaturation only if this
ratio is larger than 1,0 (saturation).
Supersaturation is the driving force of crystallization: crystal growth (speed of crystallization) depends very
much on this parameter. High supersaturation means faster crystal growth and vice-versa. There is no
crystal growth if supersaturation is less than 1,0, in which case instead of growing, already existing crystals
begin to dissolve. It is important to emphasise that supersaturation is a complex multivariable function of the
liquid phase (mother liquor) parameters and should be calculated taking into account all of its governing
parameters:
Supersaturation = f(C, Q, T, m, b, c) (Eq. 1.)
where:
C : syrup / mother liquor concentration (%)
Q : syrup / mother liquor purity (%)
T : temperature (˚ C)
m, b, c : syrup quality parameters (-)
Syrup quality parameters are discussed in detail in Ch. 12 APPENDIX.
It follows from its definition that, among others, concentration of the mother liquor should be measured online, undisturbed by the presence of crystals in the massecuite in order to be able to calculate it.
2.3 Seeding methods
Seeding is a very important step in the process of crystallization, which has a large influence on the quality
of the product. When completed, the crystals begin to grow in size, if supersaturation is larger than 1,0.
2 SUGAR CRYSTALLIZATION IN BRIEF
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CRITICAL SUPERSATURATION TO START NUCLEATION
1,1
1,11
1,12
1,13
1,14
1,15
1,16
1,17
1,18
1,19
1,2
74 76 78 80 82 84 86 88 90 92 94 96 98 100 102
SYRUP / MOTHER LIQUOR PURITY (%)
SUPERSTURATION.
TEMP.
60 C
TEMP.
70 C
TEMP.
75 C
TEMP.
80 C
Shock seeding is t he traditional way of seeding. It relies on the building up of high supersaturation in the
solution, when a small amount of seed crystals entered into the pan results in the formation of new crystals
(nucleation). The number of these crystals keeps growing as long as the value of supersaturation is above a
“safe” (nucleation-free) limit. The final number depends very much
• on the actual value of supersaturation, and
• on the time (time of nucleation) spent in the region of high supersaturation above the “safe” limit.
There are at least 3 important parameters in this method of seeding:
1. the actual value of supersaturation maintained in the “seeding point” and during nucleation;
2. the length of nucleation;
3. the limit value of supersaturation above which nucleation begins, if there are already crystals in the
solution.
Point 1. calls for a reliable measurement of supersaturation.
Point 2. has some difficulties of its own, too. How to determine the correct length of nucleation? The method
of trial and error can only be used, if supersaturation was the same all over the trials, which again calls for its
measurement. Even if it is known, in case of manual control of crystallization is it possible to ensure exactly
the same time for nucleation from strike to strike, even during the night shift?
Point 3. requires the knowledge of the critical supersaturation, above which nucleation begins in the
presence of already existing (seed) crystals. There are not many reliable data on this limit. A recent
publication (see below) provides data depending somewhat on syrup purity and temperature, too (the
dependence on temperature is more pronounced with low-purity syrups). In case of high syrup purity (larger
than 94 %) this supersaturation limit is about 1,12…1,13. An important point is that the formation of new
(often unwanted) crystals can begin any time supersa tur at io n excee ds the criti ca l super sat ur atio n limi t.
Fig. 2.1
(This figure is based on the equation published in:
M.Saska: Boiling point elevation of technical sugar cane solutions and its use in automatic pan boiling.
International Sugar Journal 2002, VOL. 104., No.1247., 500-507).
Fig.2.2 shows some of the trends typical of shock seeding. It is evident that shock seeding has quite a few
uncertainties and consequences, which make its use in modern practice unde sir able .
2 SUGAR CRYSTALLIZATION IN BRIEF
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Supersaturation
SEEDING POINT
Density
Level
Motor power
Draw in Concentrate
Graining
Boiling Boiling Discharge
up
Supersaturation
Density
Level
Motor power
SEEDING POINT
Draw in Concentrate Graining Boiling Boiling Discharge
up
Fig. 2.2
Full seeding is the advanced mode of seeding. In ideal case there are no new crystals formed during
seeding: the full required crystal crop is supplied during seeding in the form of well prepared slurry. It is
assumed that only crystal growth and no nucleation will take place during the complete length of
crystallization (during a strike in batch pans), that is the number of crystals in the end product is in ideal case
equal to the one of the seeding material.
Besides using slurry, full seeding can be implemented by using the right amount of crystal footing (magma),
too. It follows from the above that in case of full seeding and during the complete crystallization
supersaturation must not exceed its limit value. This requirement may result in somewhat longer times of
crystallization than accustomed, but will result in better sugar quality.
Fig.2.3
Fig. 2.3 shows some of the trends typical of full seeding.
2 SUGAR CRYSTALLIZATION IN BRIEF
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NOTE:
The use of slurry (or crystal footing) alone is no guarantee for correct full seeding. Besides the right amount
of slurry or footing (with the right number of crystals in it) supersaturation must not exceed its limit value.
2.4 Crystal content
Good control of the process of crystallization requires some information on the crystal content of the
massecuite, too. The amount of sugar needed to feed the growth of crystals increases as the surface area of
the crystal mass increases. Feed syrup is supplied to fill the need.
The control of crystallization in a vacuum pan, for example, should be a co-ordinated process. Control
parameters, like vacuum, heating steam (vapour) pressure, feed syrup input are connected in a complex
way to the massecuite parameters. The actual value of supersaturation depends on quite a few parameters
(see Eq. 1.) From these, concentration depends on the rate of evaporation and syrup feed, while
temperature is basically determined by the absolute pressure above the massecuite.
In batch crystallization some indirect measure of crystal content is being used to signal the end of the strike.
2.5 Product quality and supersaturation
The importance of supersaturation in product quality can not be overstated. Its role in seeding has already
been discussed, while Fig. 2.4 (scale: 1 by 1 mm) proves its effect all over the strike. In this figure a fairly
wide crystal size (from 1 mm to perhaps 0,05 mm) distribution can be observed. Most probably there were
much smaller size crystals, too, but they had escaped through the screen of the centrifuge only to increase
the amount of recirculated crystallized sugar in the green syrup (Fig. 2.6). It is evident that the smaller
crystals (the “young generation”) are due to spontaneous nucleation in the later phases of the strike. These
crystals therefore did not have time enough to grow to a larger size till the end of the strike (it is assumed
that the size of the seed crystals (the “old ones”) was fairly equal).
Fig. 2.4
In Fig. 2.5 (scale: 1 by 1 mm) among well developed crystals quite a few conglomerates (a cluster of
mutually intergrown crystals) of different sizes can be observed.
Fig. 2.5
conglomerates
10
10
Product
Crystals
F
conglomerates
Recirculated
sugar
Tank
Product
screen
Melter
Mixer
Centrifugals
2 SUGAR CRYSTALLIZATION IN BRIEF
It has been proved that formation of conglomerates mostly happens when the size of the crystals is in the 40
to 250 micron range. This means that the formation of conglomerates in the early phase of crystallization
(not long after seeding) results in large conglomerates at the end of the strike, while smaller conglomerates
in the end product are due to unwanted nucleation (because of too high supersaturation) in the later phases
of the strike. Bad circulation, probably resulting in high local supersaturation in some parts of the pan also
contributes to the formation of conglomerates.
It is quite common nowadays that special products require well defined grain sizes, which call for a tight
crystal size distribution. This can be achieved by good boiling control (including, of course, good control of
supersaturation), or by screening of the product, if it has a wide size distribution. This later method, however,
requires additional machinery , time and ener gy and natur ally incre ase s the cost of produ cti o n.
Besides wide crystal size distribution conglomerate content also contributes to poor product quality. It is well
known that the colour of the product has strong correlation to conglomerate content, because intergrown
crystals are more likely to retain some of the mother liquor during centrifuging. If conglomerate content is
high, product colour can only be improved with the excessive use of water in the centrifuges, which will
result – because of dissolution - in consider ab le los s of the cry stal mass.
2.6 Cost of production and the major parameters
It has bee n demonstrate d that wide crystal size distribution and conglomerates of varying sizes in the end
product are due to excessive supersaturation, which, if not controlled properly, can be present during the
complete course of crystallization (Figures 2.4 and 2.5). This proves that statements on the decreasing
importance of supersaturation after seeding has been completed are totally unfounded and false.
Conglomerate and fines content have very important effect on the cost of production. Too high fines content
makes centrifuging difficult and results in considerable loss of already crystallized sugar through the screen
baskets of the centrifuges. It is difficult to determine the amount of this loss and quite often it is neglected. It
should be realised, that the number of strikes per shift, often used in practice, is not a correct measure of the
rate of production. Fines and conglomerates result in recirculated sugar only to be melted, concentrated and
crystallized again, the end result of which is
• waste of time and energy,
• decreased effective yield of product sugar per strike and shift,
• increased use of water and
• increased cost of production.
It is well known that the speed of crystallization is higher if supersaturation is higher, that is the rate of
production increases with increasing supersaturation. It is therefore tempting to push production by
maintaining high supersaturation, but exceeding the safe limit, where spontaneous nucleation begins and
the risk of conglomeration increases, too, is accompanied with the unpleasant consequences discussed
above.
Selecting the correct supersaturation set point trajectory for a strike is therefore a kind of compromise (or
optimisation). However, any type of supersaturation control is un-conceivable without the correct on-line
measurement of supersaturati on.
Green liquor
and fines
Fig. 2.6
ines and
2 SUGAR CRYSTALLIZATION IN BRIEF
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2.7 Common instruments in use for crystallization control
There are two major types of data needed for good control of crystallization:
1. supersaturation, and
2. information related to crystal content.
The basic requirements concerning the sources of these data are:
accuracy:
supersaturation : fairly high,
crystal content : modest;
in - and on-line instruments:
should provide reliable data in real time during the full course of crystallization;
long-term stability:
it is a basic requirement.
Besides instruments providing data on vacuum, massecuite temperature, level and vapour pressure in the
calandria, common instruments in use for boiling control measure
• electrical parameters of the massecuite (conductivity, conductivity and capacitance (RF sensors),
• viscosity / consistency,
• stirrer motor consumption,
• density / solids content (nuclear),
• density / solids content (microwave),
• boil ing poi nt rise and
• refractive index.
None of these instruments provide reliable and quantitative data neither on supersaturation, nor on
crystal content, the real massecuite parameters that matter.
Conductivity is due to the presence of different types of ions in the syrup or mother liquor. It depends on
several parameters like concentration, composition and amount of non-sugars present, crystal content and
temperature. It certainly has (through syrup / mother liquor concentration) some correlation to
supersaturation (see Eq. 1.), but due to changes in other parameters governing it, it is far from being able to
provide reliable information on supersaturation.
Capacitance (RF sensors) depends mostly on the water content of syrup / mother liquor in a unit volume of
massecuite, therefore, besides concentration it show s stron g depen den ce on crys tal con tent .
Viscosity of the syrup / mother liquor depends on their concentration and temperature, but instruments in
use for boiling control do not have temperature compensation feature.
Consistency is the property of the liquid / solids (mother liquor / crystals) mixture. Viscosity / consistency are
measured in crystallization control practice by the same instrument. Consistency, however, sharply
increas es with incre asing c rystal content. At the end of a strike consistency can be 20-30 times larger than
the viscosity of the mother syrup alone.
Stirrer motor current or power consumption provide data on viscosity / consistency in a different form.
Density of the massecuite comes from two sources: density of the mother liquor and that of the solid
crystals. Besid es t he se the crystal to mother liquor ratio in the massecuite will determine its value.
Solids content of the massecuite is similarly determined by the solids content of the mother liquor, that of the
crystals and by the crystal to mother liquor ratio.
The common features of all instrument types discussed above are:
1. None of them is able to provide selective and accurate enough information on mother liquor
concentration in the presence of crystals, therefore they are unfit to give even approximate, indirect
information on supersaturation all over a strike (see Eq. 1).
2. Having completed seeding all instruments discussed above provide data which are more and more
governed by the increasing crystal content. It is logical therefore that these instruments can be put to good
use only to provide – though indirect and only approximate - information on crystal content.
There are only two principles of measurement which can be used to measure syrup concentration
selectively even in the presence of sugar crystals.
Boling point rise of a solution depends – among others – on its concentration, therefore it is correlated to
supersaturation. Supersaturation, however, is a multivariable function of several parameters. On the other
hand: boiling point rise depends on syrup / mother liquor purity and non-sugar composition, too. Boiling point
2 SUGAR CRYSTALLIZATION IN BRIEF
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rise is small with high-purity syrups and therefore requires very accurate measurement. Due to these
problems its use in the determination of supersaturation with the required accuracy and stability is very
questionable.
Refractive index of a solution has very strong and well-known correlation to its concentration. The
principle of measurement is in use all over the world since over one and a half century in laboratory,
and nowadays in process refractometer types, too. The data provided meet the requirements stated
earlier regarding its use in the calculation of supersaturation.
Summing up:
1. Supersaturation is the most important parameter of crystallization.
2. Supersaturation is a multivariable function of several syrup / mother liquor parameters (see Eq. 1).
3. Common instruments in use measure only a single parameter of the syrup or massecuite, therefore they
are unable to provide real quantitative data on supersaturation.
4. Supersaturation can only be calculated on-line by taking into account all of the parameters that govern
it. It is therefore logical that reliable and accurate on-line data on syrup / mother liquor concentration
are required. The only way to get them is by the use of a reliable process refractometer.
5. Information on supersaturation and on crystal content (even in indi rect form) is required for advanced
boiling control.
2.8 Mounting the K-PATENTS refractometer
The K-PATENTS process refractometers have proved their worth in thousands of applications including
crystallization in the sugar industry worldwide. They consist of 2 main parts:
• the Sensor Head (1 or 2) and
• the Indicating Transmitter
connected by a 10 to 100 m long cable.
Mounting the Sensor Head.
In crystallizer applications it is recommended to use the long probe version providing longer insertion length.
Selecting the best location to mount the Sensor Head is usually a case of compromise. Crystallizers are far
from being perfect: despite the use of stirrers, circulation of the massecuite becomes more and more
sluggish when the crystal content increases. This means that syrup / mother liquor concentration and
temperature, which have large influence on supersaturation will not be the same in the full massecuite
volume. The following considerations should be taken into account:
1. Select a location, where measured concentration is representative for the largest volume of the syrup or
massecuite. This requirement means that locations close to the feed syrup entry and above the calandria
should be avoided. Too short distance from the entry point results in misleading data valid for a diluted
massecuite in a relatively small volume. A too fast drop of measured concentration after opening the feed
valve is real cause for concern.
2. Supersaturation increases with decreasing temperature if syrup / mother liquor concentration is kept
constant. This means that highest supersaturation is expected where temperature is the lowest.
Temperature is the lowest at the surface of the massecuite, while it is the largest just above the calandria.
Naturally, the rising surface can not be followed with the sensor. In practice temperature in the pan bottom is
fairly close to surface temperature.
In practice, unfortunately enough, feed syrup most often enters the downtake just above the calandria or at
the lower end of the downtake. These are rather questionable designs because of two reasons:
• Due to the increasing difference between the density of the massecuite and that of the feed syrup due
to increasing crystal content, syrup entering the pan reverses direction and flows upwards in the downtake,
working more and more against the much needed circulation of the massecuite.
• This design is in complete disregard of the needs of the on-line measurement of any massecuite
parameter (see point 1 above).
A much better solution is when feed syrup enters the pan under the calandria through a circular ring pipe.
Feed should be distributed and directe d upwar ds at sever al l ocat ion s around the pan w all. T his soluti on
• instead of degrading, improves massecuite circulation, and
• provides good location under the feed pipe for instrument sensors.
Figure 2.7 shows recommended sensor locations for the two cases.
2 SUGAR CRYSTALLIZATION IN BRIEF
13
13
Fig. 2.7 Recommended sensor head locations
NOTE:
Sensor location in a crystallizer is a problem independent from the type of sensor used. If a separate
temperature sensor is used, it should be mounted close to the refractometer Sensor Head. The same
applies to massecuite density and solids content (brix) sensors as well.
Mounting the Indicating Transmitter
It is general practice to mount the Indicating Transmitter close to the vacuum pans. The enclosure must not
be exposed to rain or direct sunshine. Avoid vibration.
FURTHER READING:
1. L. Rózsa : On-line monitoring of supersaturation in sugar cry stal liz ati on
I.S.J., 1996, 98, 660-675
2. L. Rózsa : Sensor performance in monitoring of supersaturation
I.S.J., 1997, 99, 263-268
3. L. Rózsa : The SeedMaster device
I.S.J., 1998, 100, 601-607
4. L. Rózsa : Sucrose Solubility in Impure Cane Sugar Solutions
i.S.J., 2000, 102, 230-235
5. L. Rózsa : Sensor Selection: Still an Issue in Sugar Crystallization Control
PHILSUTEC Convention 2003, Bacolod City, PHILIPPINES
6. L. Rózsa : SeedMaster 2: A universal crystallization transmitter and automatic seeding device
I.S.J. 2006, 108, 683-695
7. L. Rózsa : Sugar crystallization: Look for the devil in the details – Part 1
I.S.J. 2008, 110, 403-413
8. L. Rózsa : Sugar crystallization: Look for the devil in the details – Part 2
I.S.J. 2008, 110, 729-739
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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DENSITY
THIRD PARTY TRANSMITTER :
DENSITY
MOTOR CONS.
THIRD PARTY TRANSMITTER:
MOTOR CONSUMPTION
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER AND SEEDING
DEVICE
3.1 SeedMaster 2 description
The heart of SeedMaster 2 is a high performance computer specifically designed to calculate, displa y and
transmit all of the vital parameters characterising sugar crystallization simultaneously for up to 2 crystallizers.
Besides that it can perform reliable automatic seeding of the crystallizers as well. Both features require the
input of some data measured on-line by 1 (or 2) K-PATENTS process refractometer(s) and by some selected
instrument(s). Input of a few laboratory data and status information (digital inputs) are also required.
Based on these data SeedMaster 2 is able to calc ula te 7 massecuite parameters per crystallizer in real tim e,
only 2 of which are considered adequate for the advanced control of crystallization.
Some of these parameters (for example: crystal content, mother liquor purity, mean crystal size etc.), though
they are important ones, are usually rarely determined by the local laboratory, if at all. Due to the time delay
(dead-time) involved, these data, however, are more or less useless in closed loop, real time control of
crystallization.
Other instruments in use provide data only on a single massecuite parameter.
Fig. 3.1 SeedMaster 2 serving 2 vacuum pans
3.2 SeedMaster 2: a front-end device
The device was designed to be used as a “front-end” instrument mounted close to the vacuum pans or
crystallizers in order to provide all of the information required by operating personnel on site. It has a large
backlit LCD display and a keyboard (Fig. 3.2). Naturally enough, it has advanced digital communication
features to send a large amount of acquired and calculated data on-line to a Process Control System, too.
The LCD display is specified to operate in the 0 – 50 C temperature range (environment) and this applies to
SeedMaster 2 as a whole, too.
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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15
Fig. 3.2 The SeedMaster 2 enclosure
(Display: supersaturation and cry stal co ntent )
3.3 Principle of operation
Contrary to commonly used sensors that measure massecuite parameters only indirectly linked to the really
important ones (supersaturation and crystal content), SeedMaster 2 was designed to provide information online on all of the parameters which are important for the up-to-date control of crystallizati on .
Its operation is based on the use of the K-PATENTS process refractometer, which became the workhorse of
different industries, including sugar, when accurate on- and in-li ne measu rement of liquid concentration is a
must. Syrup / mother liquor concentration data are not disturbed by the presence of crystals, steam and
vapour bubbles and the colour of the liquid. At the same time the refractometer provides data on massecuite
temperature as well. This means that data on C and T (concentration and temperature) in Eq. 1. are directly
provided by the refractometer. Though not advised, it is possible to use a separate temperature probe and
transmitter, too. Besides these data information on mother liquor purity Q is also required for the on-line
calculation of supersaturation.
Mother liquor purity is equal to feed syrup purity only up to the point of seeding. When the crystals begin and
continue to grow, mother syrup purity begins to drop accordingly. It is therefore not constant during the strike,
and should be calculated on-line together with changing crystal content. This, however, needs the use of
additional on-line data (“Third input”) from some already existing sensor (density, massecuite solids content
(brix), or stirrer motor consumption).
NOTES:
1. The use of stirrer motor power or current consumption as “Third input” is limited to batch vacuum
pans operating without strike cut(s), that is without discharging some part of the massecuite before
the end of the strike. The trend of motor consumption data should look like one of those shown in
Fig. 7.5 or Fig. 7.6.
2. As a last resort, if none of these sensors is available, a single data from the laboratory (updated
from time to time) on crystal content (% by volume) when dropping the charge (vacuum pans
operating in batch mode without strike cut(s)) can be used.
Finally, it is well known that feed syrup quality, characterised by its “m”, “b” and “c” parameters can show
considerable changes, which have to be taken into account when calculating the massecuite parameters.
Syrup quality parameters should be determined by the local laboratory (see: APPENDIX). If it is not possible,
data typical for beet and cane syrups are available. Besides these some additional laboratory data are also
required.
SeedMaster 2 operates in two differ ent mod es:
1. in “Stand-by mode” it is waiting for the start (“activation”) of a new strike (vacuum pans
operating in batch mode);
2. in “Active mode” it is carrying out all of the calculations and operations it was designed for
(batch vacuum pans and continuous crystallizers).
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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Data base
START On-line inputs
program once Parameters
every 10 sec Digital I/O
Calculated outputs
Archive data
Strike
ACTIVE?
ACTIVE YES STAND-BY
MODE MODE
Calculations operations
Archive END
data
Seeding
operations
Decision based on
THIRD INPUT
MASS. DENSITY MASS. SOLIDS CONT. MOTOR CONS. LAB. CR. CONT.
Calculations Calculations Calculations Calculations
END
Fig. 3.4 The basic SeedMaster 2 operations
Based on the calculated data SeedMaster 2 can be programmed to carry out automatic seeding of the
crystallizer on its own, when
• supersaturation, or
• massecuite density
becomes equal to the supersaturation or density set-point selected by the technologist or pan operator.
Actual seeding is carried out by opening the seed valve (digital output) for a pre-set time interval.
If seeding of the crystallizer is carried out not by SeedMaster 2, but by another device (a control system, for
example), or by the operator, SeedMaster 2 must be notified accordingly by a digital input, or via digital
communication.
All operations discussed above can be performed independently with two crystallizers at the same time.
3.4 Calculated data
Based on the information received SeedMaster 2 carries out involved calculations on-line. These, and one or
the other of the measured data used (density, solids content, motor consumption, or laboratory crystal
content data) are combined providing information on 7 massecuite parameters (set of massecuite
parameters) per crystallizer. These are:
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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17
1. supersaturation (-)
2. crystal content (% by volume)
3. mother liquor purity (%)
4. massecuite density (kg / m)
5. massecuite solids content (%)
6. massecuite consistency (%)
7. mean c rystal size (mm)
Parameters No.1. and No.2. are the important ones for the advanced control of crystallization.
Parameters No.1. … No.3. and No.7. represent a drastic change in the type of information available in
real time for crystallization control, while No.4….No.6 provide accustomed data.
NOTES:
1. Any 2 out of the 7 (per crystallizer) listed above can be selected for transmission by standard (0…20 mA,
or 4…20 mA) current output.
2. All of these and some other data can be transmitted to a PC (Personal Computer), or PCS (Process
Control System) via digital communication.
3. Mean crystal size data are approximate and valid only if full seeding is practiced and no dissolution
of crystals or further nucleation takes place during crystallization.
3.5 On-line data inputs
The 2 obligatory on-line (real-time) data inputs required for the correct operation of SeedMaster 2 are:
1. syrup / mother liquor concentration, and
2. massecuite temperature.
It is highly recommended to use a third on-line data input (“Third input”) as well, which can be selected
from those listed below:
3. massecuite density (kg / m), or
massecuite solids content (%), or
stirrer motor power consumption (kW), or
stirrer motor current (A).
It does not matter what kind of instrument (nuclear, microwave etc.) is being used to measure density, or
solids content. If stirrer motor consumption provides the 3
preferred.
rd
data input, power consumption (kW) data are
3.5.1 Receiving syrup concentration data from the K-PATENTS refractometer(s)
There are several ways to transmit concentration data originating from a K-PATENTS refractometer to
SeedMaster 2 (see Ch. 7.2):
1. Standard current transmission (4 – 20 mA).
The transmitter can be the refractometer itself, or the standard current may come as current output from a
DCS-, or PLC-based Process Control System (PCS) already receiving the data from the refractometer. In this
case an analogue input channel of SeedMaster 2 sh oul d be used.
2. Digital communication using ports COM1, COM2, or COM3.
It is possible to transmit concentration (and temperature) data measured by K-PATENTS PR-01-S type
refractometer(s) by using serial data communication (RS232, RS422, RS485). SeedMaster 2 has 3 serial
ports (COM1, COM2, COM3). Two of these can be used to receive data directly from 2 PR-01-S type
refractometers at the same time . Cable length should be short, not exceeding 15 meters.
3. All data exchange (inputs and outputs) between SeedMaster 2 and a PCS can be implemented by
using one of the COM1…COM3 ports and MODBUS SLAVE (ASCII RTU) protocol.
4. Data input (concentration and temperature) to SeedMaster 2 from a K-PATENTS PR-23 type
refractometer with 1 or 2 sensor heads can be implemented by directly connecting them using the standard
ETHERNET connection and UDP / IP K-PATENTS refractometer protocol.
5. All data exchange (inputs and outputs) between SeedMaster 2 and a PCS can be implemented by
using the standard ETHERNET connection and TCP / IP MODBUS TCP protocol.
3.5.2 Receiving temperature data
Massecuite temperature is always measured by the sensor probe of the K-PATENTS refractometer and may
be available for transmission as standard current (4 – 20 mA) output (option). The Indicating Transmitter of
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
18
18
the refractometer has (depending on the model used) two, or only a single current output. It is possible to use
an independent temperature sensor and standard current transmitter to transmit temperature data to
SeedMaster 2 as well. SeedMaster 2 has 2 (optional) RTD Pt100 type (Resistance Temperature Detector)
inputs as well. In these cases the temperature sensor should be located as close to the refractometer sensor
head as possible in order to measure the same sample temperature. From time to time re-calibration of the
temperature transmitter is advised.
Temperature measured by the refractometer can be transmitted (together with concentration data) by using
digital data communication (C OM1, COM2, COM3 and ETHERNET ports), too.
All data input versions listed with concentration data input (3.5.1) are available.
NOTE:
It is preferred to use temperature data measured by the refractometer.
3.5.3 Selecting the “THIRD INPUT” transmitter
Whenever available a “THIRD INPUT” transmitter should be used. If there are more than one available from
those already listed, massecuite density or solids content data are preferred. From these two the one offering
higher accuracy and stability should be used. Based on practical experience it is rather difficult to calibrate
and verify these devices. It is possible to make slight corrections in the data provided by them in SeedMaster
2 itself in order to achieve a better match with more accurate refractometer and laboratory data.
If stirrer motor data are used it is preferred to use motor power consumption (kW) data, because they better
reflect the mechanical power required to drive the stirrer (voltage fluctuations and the changing power factor
are also taken into account). As a last resort, motor current data can also be used.
NOTE:
The use of stirrer motor power or current consumption as “Third input” is limited to batch vacuum
pans operating without strike cut(s), that is without discharging some part of the massecuite before
the end of the strike. The trend of motor consumption data should look like one of those shown in
Fig. 7.5 or Fig. 7.6.
3.5.4 Using laboratory data instead of “THIRD INPUT”
It is always preferred to have on-line feedback (that is: on-line information from one of the instruments listed).
However, if there is no instrument available to use as “THIRD INPUT”, laboratory data on crystal content (%
by volume) at the end of a strike can be used with batch vacuum pan applications. In this case the instrument
carries out involved calculations in order to simulate the process of crystallization on-line. Based on
occasional crystal content data from the laboratory, the simulated process of crystallization is adapted by the
instrument using these data from the laboratory. All feat ures of SeedMaster 2 are available.
3.5.5 Optional data input
An optional LEVEL transmitter can be connected to one of the analogue input channels of SeedMaster 2.
The level data may come from a PCS via digital communication, too. The use of level data is optional: if
available, they are used to refine some of the calculations and to implement a smoo th transition from one
feed syrup to an other one, if feed syrups with different purities are used in the same batch strike. It can
.provide additional information on site for the pan operator, too. If there is no on-line data on level, instead of
level mean crystal size will be displayed on the Main Display.
3.6 Digital inputs
The 2 digital inputs (per pan) are typically contact (relay or switch) types. An “ACTIVE” digital input can be
configured either as an OPEN, or CLOSED relay (or switch) contact.
3.6.1 “STRIKE ACTIVE” input DIN1
SeedMaster 2 can be operated in “Stand-by”, or in “Active” mode (Fig. 3.4). In Stand-by mode it waits for the
start of a new strike (batch pans) and no calculations are performed. Displayed data might be not correct.
The Active mode should be evoked by the start of a new strike (feeding syrup in the pan begins), and s h o uld
usually end with the drop of the charge and motor switch OFF. In the time between two active strikes
(SeedMaster 2 in Stand-by mode) the pan is usually washed and is under normal pressure. Temperature and
concentration data can be quite far from their normal ranges.
Information on the “ACTIVE “status of a pan or crystallizer might come from 3 sources, namely:
• from a relay or switch contact (digital input DIN1), or
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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19
SEEDED DIN2
SEEDED DIN2
WAIT
STRIKE 1 ACTIVE
STRIKE 2 ACTIVE
Time
Time
S T R I K E A C T I V E
DIN1
• from the fact, that the current or power consumption of the stirrer motor exceeds a pre-set low
limit (cut off value, motor ON/OFF)), or
• from a PCS via digital communication.
NOTES:
1. The source of the “STRIKE ACTIVE” information can be selected from the above 3 during configuration.
If motor consumption or information from a PCS is being used to synchronise the operation of SeedMaster 2
to crystallizer status, digital input DIN1 can be left un-connected.
2. If motor consumption (power, or current) is used as “STRIKE ACTIVE”, un-intentional stop (due to mains
failure, motor problems etc.) of the stirrer motor during a strike will be treated as an “End of strike” signal.
3. It is advised to use a contact input for “STRIKE ACTIVE” signalisation.
3.6.2 “SEEDED” input DIN2
In order to perform the calculations correctly SeedMaster 2 needs information on the seeding of the pan.
There is no need for this input if seeding of the pan is carried out by SeedMaster 2 itself, that is if
• AUTOMATIC SEEDING was configured, or
• the operator uses the “MANUAL SEEDING” feature regularly (not advised).
However, if seeding is carried out
• either by an independent process control system (PCS), or
• the PCS commands SeedMaster 2 to do the seeding, or
• manually by the operator (pan-man) without using the “MANUAL SEEDING” feature of
SeedMaster 2,
the device must be notified on the seeding of the pan by a digital input lasting for at least 20 seconds.
In this case information may come in the form of a digital input (DIN2) signal, or via digital commu nication
from an independent control system (PCS).
NOTES:
1. Failing to provide information on seeding when needed will result in erroneous op er ation.
2. When SeedMaster 2 receives information from a PCS on seeding, it will operate the same way as it would
if MANUAL SEEDING were configured, that is it will OPEN the seeding valve (DO2, if connected) for the
configured Ton time.
3.6.3 “CHANGE FEED SYRUP” input DIN3.
If instead of a single one, 2 or 3 (maximum) feed syrups having different syrup purities are to be fed to the same batch strike the device must be informed on the execution of the change. One way to do it is to use a digital input (DIN3).
In this case information on purity and pan level may come in the form of 4-20 mA current from a PLC or DCS.
If there are no level data available, the SeedMaster 2 will use typical simulated level data in the 35-80 %
range. Operation of the DIN3 digital input will step the feed syrup purity to the one determined by the actual
current input (maximum 3 times). (For more information on feed syrup change see: 5.1.4 and 8.2.2).
3.7 Data outputs
3.7.1 Data available for transmission
Besides the 6 (out of 7) massecuite parameters 4 additional ones per pan are displayed on the LCD of
SeedMaster 2. Altogether 11 are available for transmission to an other device (PCS).
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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20
Set of massecuite parameters:
1. supersaturation (-)
2. massecuite density (kg / m3)
3. massecuite solids content (%)
4. crystal content (% by volume)
5. massecuite consistency (%)
6. mother liquor purity (%)
7. mean c rystal size (mm)
Additional data:
8. syrup / mother liquor concentration (%)
9. stirrer motor consumption (if used) (kW, or A)
10. temperature (˚C)
11. level (%)
3.7.2 Standard current outputs
SeedMaster 2 hardware provides 2 standard current (4 – 20 mA, or 0 – 20 mA, configurable) output channels
per crystallizer. Any 2 out of the possible 11 parameters can be selected for transmission.
3.8 Digital (ON / OFF) outputs
There are 2 digital outputs available per crystallizer (DO1, DO2). These are implemented by switching
transistors (open collector) capable to switch 0,1 A (DC) current at 40 VDC, max.. The outputs are protected
against overload and overvoltage.
3.8.1 “SEED WARNING” output DO1
It is common practice to have the operator (pan-man) prepare the seed material (slurry) in advance and later
carefully stirring it for homogenisation, and fill it in the seeding vessel when seeding of the pan approaches.
The “SEED WARNING” output is configurable according to a supersaturation or density limit, and when this
limit has been reached the DO1 output will be turned ON activating a lamp or horn in order to signal the
operator that it is time to fill the seed slurry in its vessel. Having completed seeding this output will be turned
OFF automatically.
Alternatively this output can serve a different purpose, too. For example: if the seeding vessel has its own
small, motor driven stirrer, this output can be used to turn this stirrer ON in advance to homogenise the slurry
already filled in it.
3.8.2 “SEEDING” output DO2
Actual seeding of the pan is carried out by turning the DO2 output ON and opening the seeding valve for a
selected Ton time interval (configurable). This output will be operated in 3 cases:
• when AUTOMATIC SEEDING by SeedMaster 2 was configured,
• when MANUAL SEEDING by using SeedMaster 2 was carried out by the operator, and
• when it receives a command for seeding via input DIN2, or digital communication.
This same output can be used also when crystal footing is being used for seeding.
3.9 The man-machine interface
The man-machine interface of SeedMaster 2 consists of two main parts:
1. Parameterization of the device is basically tailoring (customizing) it to the application, taking into
account local circumstances and preferen ce s.
2. Operation of the device needs the built-in features of the different forms of data display, including
strike history, alarm and test data. Besides AUTOMATIC SEEDING it also provides a tool for MANUAL
SEEDING. Information on seeding details, strike
status and time are also displayed.
3 THE SEEDMASTER 2 CRYSTALLIZATION TRANSMITTER …
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21
STRIKE ACTIVE SIGNAL
THIRD INPUT
SEEDING
ACTIVE INSTRUMENT
CONFIGURATION
PASSWORD
COMMUNICATION
DISPLAY
INPUTS
MENU SET UP DIGITAL I / O
1 ANALOG OUTPUT
2
DEVICE PARAMETERIZATION TOOLS
MANUAL OPERATIONS MANUAL SEEDING
CHANGE FSYRUP
TREND
STRIKE HISTORY
DISPLAY
STANDARD DISPLAY
SYTEM INFORMATION
TEST DATA
DEVICE OPERATION TOOLS
Fig. 3.5 The main branches of the SELECTION TREE
4 TECHNICAL DATA, MOUNTING AND ELECTRICAL CONNECTIONS
22
22
4 TECHNICAL DATA, MOUNTING AND ELECTRICAL CONNECTIONS
SeedMaster 2 is based on the use of a high-power 32 bit microprocessor and a high capacity (32 MB)
memory operating under a real-time operating system. This, the application program of the device together
with parameters, measured and calculated data are stored in CF (Compact Flash) memory. Parameters,
calculated and archive data are stored every minute in the memory, therefore eventual loss of power supply
will not result in loss of these data. The real-time clock chip (DALLAS DS12887) used in the device has its
own lithium battery and needs replacement only after 10 years.
In order to increase reliability and to reduce servicing, no potentiometers are used in the instrument.
4.1 Specifications
Main device features
1. On-line calculation, display and transmission of up to 7 massecuite parameters and up to 4
additional monitored data during sugar crystallization for up to 2 pans simultaneously.
2. Automatic seeding of vacuum pans based on calculated supersaturation or density set-point for
seeding selected by the local technologist.
3. Collecting all calculated and measured data for the last 4 strikes in strike history archives, which can
be displayed as trends with appropriate time data. Brief (numerical) supersaturation strike history
(last 4 strikes).
4. Advanced communication features including the Ethernet.
5. Large LCD numeric and graphic display, robust design.
Data available for transmission
1. Calculated data (all over a complete strike):
1. Supersaturation (-)
2. Crystal content (% by volume)
3. Density (kg / m)
4. Consistency (%)
5. Solids content (%)
6. Mother liquor purity (%)
7. Mean crystal size (mm)
2. Additional data monitored in real time:
1. Syrup / mother liquor concentration (%)
2. Stirrer motor consumption (if used) (kW, or A)
3. Temperature (˚C)
4. Level (optional) (%)
Inputs for calculation
1. Process inputs:
1. Syrup / mother liquor concentration measured by K-PATENTS refractometer(s)
2. Massecuite temperature measured by K-PATENTS refractometer(s), or separate
transmitter(s).
3. Third par ty tran smi tter mea s ur ing
• density, OR
• massecuite solids content, OR
• stirrer motor power, or current consumption.
4. Optional input: massecuite level.
2. Digital (ON / OFF) inputs (depending on the selected mode of operation):
1. None.
2. Maximum 3 (DIN1: “Strike active”, DIN2: “Seeded”, DIN3:”Change feed syrup”).
3. Laboratory data:
1. Feed syrup purity (%).
2. Syrup quality (“m”, “b”, “c”) parameters. Typical data and a description of a procedure to
determ ine lo cal para meter s are prov ided.
NOTE:
All inputs can be also received via digital communication.
4 TECHNICAL DATA, MOUNTING AND ELECTRICAL CONNECTIONS
23
23
Calculated outputs
1. Analog (0-20, 4-20 mA) outputs:
Any 2 of the 7 calculated massecuite parameters (per pan).
2. Digital (ON / OFF) outputs:
1. DO1: Warning on approaching seeding (programmable).
2. DO2: Opening the seeding valve for a selected time interval.
NOTE:
All calculated and measured data can be also transmitted via digital communication.
Process interface
Inputs
1. Analog current 8 channels
Symmetr ical, galvanically isolated
Range 0(4)-20 mA, keyboard selectable
Input impedance 100 Ohm
Common mode voltage 50 V max.
2. RTD (Pt 100) (option) 2 channels
4 wire connecting mode
3. Digital (ON / OFF) 8 channels
Signal sources: passive, contact or open collector
active, + 24 Vdc
automatic signal detection
Outputs
1. Analog current 4 channels
Galvanically isolated
Range 0(4)-20 mA, keyboard selectable
Max. load 600 Ohm
2. Digital ON / OFF) 4 channels
Isolated open collector,
overvoltage and short circuit protected
3. Power supply for transmitters 1 X 24 Vdc, 200 mA max.
4. Device Status (ON/OFF) Operating / Error
Communication
1. Serial (COM1, COM2, COM3) 3 ports
Galvanically isolated
Standards RS232, RS422, RS485 (keyboard selectable)
Control signals CTS, RTS (keyboard selectable)
Baud rates 1200…38400 Baud (keyboard selectable)
Length of cable RS232 15 m max.
RS422 /485 1200 m max.
Protocols K-PATENTS refractometer protocol
MODBUS SLAVE (ASCII, RTU)
2. Ethernet 10 6 100 Base T
Connector RJ45
Protocols TCP / IP, MODBUS TCP,
UDP / IP (K-PATENTS refractometer protocol)
Front panel
Display 5,7 ‘ QVGA 320x240 graphic LCD
Keyboard Membrane switches with flexible foil cover
LED indicators Power, Run, Alarm
Power supply 100…240 V ac, 50 / 60 Hz; 10-25 VA
24 (18…30) Vdc
4 TECHNICAL DATA, MOUNTING AND ELECTRICAL CONNECTIONS
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24
NOTE:
AC and DC types of supply can be connected to the device at the same time. When AC supply is available it
will be selected for use, otherwise the DC supply will be the active one. Switch-over from one to the other is
automatic and bumpless.
Temperature range (ambient)
Operation 0…50 ˚C
Storage - 25…70 ˚C
Enclosure
IP66, NEMA 4X
Size (mm / inch) H: 267 / 10,5; W: 226 / 8,9; D: 159 / 6,25
NOTE:
The SeedMaster 2 enclosure is identical to the one used by the Indicating Transmitters of the K-PATENTS
refractometer family and should be mounted taking into account the same considerations, that is:
• do not expose it to direct sunlight and rain, or splash water,
• avoid vibration,
• mount it vertically on an upright surface in a dry and well-lit area,
• do not drill mounting holes in the enclosure.
Fig. 4.1 SeedMaster 2 dimensions and mounting feet measures
4.2 Electrical connections
4.2.1 Power supply
Power to the instrument must be connected by a cable with protective earth connection. Even if DC supply is
used (see Ch. 4.1), in order to maintain the accuracy of the analog inputs the protective earth connection
must be used via the mains connector.
NOTES:
1. There is no mains switch in the instrument! An external power switch should be used.
2. Check if your mains voltage specification and that of the instrument are identical before first
switching on the instrument!
WARNING!
Check if the power is off before opening the Front panel. If the red POWER LED on the Front panel is
ON, turn off the power first by unplugging the power supply cable or switch it OFF with the external power
switch.
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Fig. 4.2 Electrical connections
There are two screw-type terminals for power connection in the bottom of the enclosure (se e Fig. 4.2). The
one on the right side has 3 terminals (L: line, G: ground, N: neutral) to connect the AC power input, while the
one on the left has 2 terminals with polarity markings for 24 V DC input. Both power inputs have their
dedicated fuses.
4.2.2 Process inputs and outputs
Process inputs and outputs use printed circuit spring cage terminal blocks. There are 2 connection points
(polarity is marked) per terminal block. Just above the power input level on the left side there are terminals for
8 analog input (AI) channels (0-20, or 4-20 mA, keyboard selectable) and a 24 V DC output (PS out) to
supply power for transmitters (max. load: 200 mA).
On the same level on the right side similar terminals for 4 analog output (4-20 mA) channels (AO, channels
1…4) are located. These are followed by 4 digital output channels (DO, channels 1…4), then by 8 digital
inputs (DI, channels 1…8). The digital inputs have their common terminal point (common) in the rightmost
position. All terminal points have their appropriate polarity markings.
4.2.3 Digital communication
There are screw-type terminals on the highest level (Fig. 4.2) for 3 serial communication ports (Com1, Com2,
Com3). Their connection points are colour-coded according to the selected type of communication (black:
RS232, red: RS485, blue: RS422).
The Ethernet 10/100 port is located to the left of the Com1 port.
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4.2.4 I / O wirings
Analog input channels
Simplified 4 -20 mA Analog Input and cabeling using external Transducer power supply.
Simplified 4-20 mA Analog Input and cabeling using the internal (max. 200 mA) Transducer power supply.
Fig. 4.3 Analog input versions
Analog output channel
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Fig. 4.4 Simplified 4-20 mA Analog Output and cabeling.
Digital input channels
Simplified Digital Input types and cabeling
Fig. 4.5 Digital input versions
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LCD
Digital output channel
Fig. 4.6 Simplified Digital Output and cabeling driving a relay.
4.3 Construction details
LCD and keyboard electronics
Fig. 4.7 Back of the front panel (protecting metal plate removed)
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Front panel
Fig. 4.8 First metal plate removed
Memory The main circuit board in the enclosure.
Fig. 4.9 Front panel and the main circuit board
Fig. 4.10 Hardware removed
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Power supply
Fig. 4.11 Power supply behind the main circuit board
Device status
There are 2 contact outputs which can be used to monitor the operation of SeedMaster 2. The 3
terminals are located in between the Com1 and Com2 serial port terminals.
Operating : Closed contact when operating
Common : The common electrical terminal.
Error : Closed contact when not in operation.
NOTE: the inputs + Sense and – Sense are not in use.
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