Frequently Asked Questions 9.2

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Installation related questions

What I do if I get "Unable to execute file: \SysCAD92\bin\SysCADMarshal.exe" during installation

Install error.png

This error may occur during SysCAD installation if user did not have administration rights to the computer. During the installation, SysCAD needs to copy the correct version of Microsoft Visual C++ Redistributable Package (vcredist_x86.exe) to the computer. If user permission issue has prevented these files from installing properly, the SysCAD installation would not complete properly.

To fix this problem, log on the computer as administrator and try to install SysCAD again.

What do I do if I get a "This application has failed to start because the application configuration is incorrect" message?

Redist error.png

This error may occur after a user has updated their version of SysCAD rather than doing a full install. It occurs because this new version of SysCAD requires a newer version of Microsoft Visual C++ Redistributable Package (vcredist_x86.exe) than is currently installed on the user's computer.

When SysCAD does start, it displays the MSVC version used on the Systems tab page of PlantModel in the field MSVC_Ver.

These commonly used redistributable files may have already been installed by a Windows update or by an update of other software packages. They are installed Side-by-Side, so different versions get installed to different folders.

To fix this, install the required Microsoft Visual C++ Redistributable Package (vcredist_x86.exe). Note that full administrator privileges are required to install this.

To get a copy of vcredist_x86.exe, either:

  • download and run the full SysCAD installation. The required Microsoft Visual C++ Redistributable Package (vcredist_x86.exe) is included as part of the install; OR
  • from a recent full SysCAD install retrieve the Microsoft Visual C++ Redistributable Package (vcredist_x86.exe) from the "\SysCAD92\Setup\MS VC Redist" folder and install this.


We do NOT recommend that you download the Microsoft Visual C++ Redistributable Package (vcredist_x86.exe) from the Microsoft website, because there are different versions of vcredist_x86.exe available, and it is difficult to find the correct version required by SysCAD.

What do I do if I get a "The application has failed to start because the side by side configuration is incorrect....." message?

Full error message is : The application has failed to start because the side by side configuration is incorrect please see the application event log or use the command line sxstrace.exe tool for more detail

This error may occur after a user has updated their version of SysCAD rather than doing a full install. It occurs because this new version of SysCAD requires a newer version of Microsoft Visual C++ Redistributable Package (vcredist_x86.exe) than is currently installed on the user's computer. The solution is to run the correct vcredist_x86.exe install. As this is a variation of the error above, follow the same solution.

Project related questions

Can Projects be upgraded easily to a new version?

  • SysCAD 9.1 projects can be relatively easily upgraded to SysCAD 9.2. Upgrade support is provided, but ongoing support in use of 9.0 is no longer provided. See Upgrade to SysCAD 9.2 for a detailed description of upgrade procedure, it can be briefly summarised as follows:
  1. Using Windows file manager copy the project, together with the corresponding configuration files, to the new equivalent SysCAD92 folder.
  2. Start SysCAD 9.2 and edit the project configuration file. This step will force SysCAD to upgrade the configuration file and the species database.
  3. Check the messages window for any warnings or errors with the species database and fix these, if any are flagged.
  4. You can then open the project in SysCAD 9.2. Before solving, check for the messages window for any warnings or errors and fix these. Exit and reload the project.
  5. Once the project load errors are resolved you can solve the model, again checking the messages window for any warnings or errors and fixing these.
  6. Once the project has solved, or converged, check the results.
  • SysCAD 9.0 is no longer supported. Projects in 9.0 should be upgraded to newer versions. See Upgrade to SysCAD 9.1.

How do I create a new project?

Once SysCAD is started, go to File | New, and create a project from there. In SysCAD whenever a new project is created you are first asked to select a configuration file. The configuration file is used for selecting species, options, data and settings that would be used by many projects. Please see Creating a New Project.

The SysCAD Tutorial documentation has step-by-step instructions on this and there is also a short video is the Tutorial section at Basic Tutorial - Starting a New Project

How do I open a new Flowsheet window?

In an existing project you may use either of the following methods:

  1. Ensure that the 'Graphics' menu is active (click on any graphics window), click on 'Graphics - New Graphics Window' and this will open a new graphics window. (Only available in SysCAD 9.2 Build 135 and later); OR
  2. Click on 'File | New', and click on the Graphics button.

Please also see Open a New Graphics Window .

What is a configuration file?

A configuration file can only be edited when all the projects are closed, from the Project menu, select Edit|Project Configuration. It has the following sections:

  1. It allows the user to select Unit Operations to be used in the project. For example, if SysCAD is running in ProBal Mode only, all the Dynamic Models can be deselected to make the list shorter. One thing to note is that the unit operation models are normally limited by the license as well, so this page need not be changed very often.
  2. It allows the user to set up information such as the normal temperature, pressure, atmospheric pressure, default species model and so on.
  3. It allows the user to select chemical compounds (already defined in the species database syscad.mdb) to be used in the project.
  4. If required, it allows the sieve series and size distribution data to be defined. Only valid for users with the Size Distribution Module (add-on).

What is in the SysCAD.mdb file?

The SysCAD.mdb file contains chemical and thermodynamic properties for compounds used in the project. The user can define many compounds in the database, but only use a subset of these in a project.

Please see:

NOTE: For new compounds to be visible in the project, they must be selected via the configuration file. (See What is a configuration file?)

My project will not converge, how can I find the problem unit(s)?

One way to troubleshoot projects that either will not converge, or are very slow to converge is as follows:

  • With the project solving, click on the ‘Errors’ button on the solver status dialog window.
  • This shows you the units in the project with the largest errors – with the biggest ones at the top and getting smaller down the list.
  • Right click on the top line (you can pause the simulation at this point, if you prefer) and you will see the following dialog:
    Find Error.png
  • You can then click on ‘Find X-001’ or ‘Access X-001’ (or whichever unit SysCAD says is causing the problem)
  • This will highlight the unit causing the problem and you can then determine why it is preventing convergence.

Once you have fixed the worst problem, the project may converge quickly, or you may need to repeat this with the next worst problem.

How do I add particle size distribution data to a project?

Firstly, you need to add size distribution to your project configuration before you can use it in a project.

Open SysCAD, but do not have a project open, and then go to ‘Edit - Project Configuration’ and choose to ‘Edit’ the project of interest.

When the configuration window opens, ensure that ‘SizeDst1.dll’ and ‘Separ2.dll’ are selected in the list of required DLL’s (just click on the left hand side of these dlls and a tick will show)

Click on the Next>>> button

You will now have a number of tabs to choose from. The first step is to select the sieve series, then set the size distribution and the actual solids species that will have a size distribution – please refer to Size Configuration.

When you have finished setting the size data in the configuration file, you can close the configuration editor.

How do I send a project to another user?

The user must zip and send the entire project folder, preferably with relative path names. For example for a project called FullPlantModel.spf zip this as

The user may optionally include the following steps:

  1. Also zip and send the CfgFiles folder. However, the required files are also contained in the project folder, so this is not essential.
  2. If the zip file is large, you may delete any files (historian data files) to reduce the size of the zip file, if required.

How do I open a project sent from another user?

The user must follow these steps:

  1. Unzip the file received from the other user following the relative path names or unzip to a new folder with the correct project name and extension. For the example above this would be FullPlantModel.spf.
  2. After the project is unzipped, using Windows Explorer, go to the project folder, e.g. FullPlantModel.spf, and open the file
    • This zip file contains 'remote' files that the project needs to run. For example, the species database, SysCAD92.mdb, and the project configuration file, etc.
    • If these files are not already on the user's computer, then this file must be extracted to the correct CfgFiles folder. Please refer to Location of Project Files if you are not sure of the location of the files.
    • NOTE: Your path for these reference files may differ to the sender. If you have used a different path, please follow the next step:
  3. If the paths of the configuration file have changed then use File - Open Project (Alternate Cfg) to open the project.

What are referenced files?

The referenced files are those written by the user, external to SysCAD. These include any Excel Reports, PGM files, reactions files, script files and driver files.

The referenced files are normally stored within the project folder.

  • Reaction files, .rct, are stored in a folder within the project called Reactions.
  • Control files, .pgm, are stored in a folder within the project called Controls.

It is a good idea to also store other reference files within the project folder as this will help to keep the project self-contained. However, it is possible to store them under other designated folders, eg, the cfgfiles folder.

It is up to the user to keep to a consistent format for good project management.

How do I create SysCAD reference files, are there any templates available?

The SysCAD tutorial has step-by-step instructions on how to create these reference files. These files are stored under the \Tutorial\cfgfiles folder. The user can use these files as templates for future work. As well, the tutorial.xls has many examples on the SysCAD reports.

How do I change a project from ProBal to Dynamic or vice-versa?

Step 1 - Ensure that your license allows you to use the desired mode.

Step 2 - Check the configuration file of the project to ensure that the desired mode is enabled (see Edit Configuration). Note that both modes can be enabled in the one configuration file (see General Configuration). NB your project must be closed for you to be able to edit the configuration file.

Step3 - Again with your project closed, edit the project settings and change the Network Solution to the desired mode. You can now open your project in the new mode.

General questions:

Why does it take a long time to check the license?

If SysCAD is taking a long time, say around 10 seconds (anything more than 5 seconds), to check the license at startup, then it is likely that an older version of the crypkey license service is installed. You need to force an install of the correct version of crypkey. This requires administrator rights. See Re-installing the Crypkey Licensing Software for details. It should usually take about 2 or 3 seconds (or up to 4 or 5 seconds) to check the license when SysCAD is started. The time taken depends on the PC and whether it is a stand-alone or network license.

How do I check what License I have?

Information can be obtained from menu command Tools - License Information. Or run the SysCAD License Utility (syscad,.exe) located in the license folder. For more information see Licensing.

How do I transfer the SysCAD license from one machine to another?

In the User Manual, there is a section on Licence Transfer, please refer to that for step-by-step instructions. Please refer to the License section for information on license related commands.

Can I have two projects opened at the same time?

If you have a stand-alone SysCAD license, then yes, it is possible. Simply start up another instance of SysCAD and load the second project. It is also possible to do this if you have a multi-user network license, but for each copy of SysCAD that is started, you will be using one of the licenses. Please note that since SysCAD together with the project can take a large amount of memory, you may be limited by the RAM you have on your PC.

I have a multi-core or multi-processor machine, will I notice a speed increase during solve and can I control how the machine uses the processors?

Since the introduction of SysCAD 8.1 the solver was designed to take advantage of multiple processors. The SysCAD software has been programmed to create 'worker threads' to divide the workload and take advantage of multiple processors. This capability has been improved in subsequent SysCAD versions.

In a flowsheet this division is done at the model level and is based on the ability to solve models in parallel given that all inputs are known. Hence if a flowsheet topology is such that after tearing (breaking recycles), a number of parallel paths exist, gains will be achieved.

If on the other hand the flowsheet consists of one long sequence of unit operations there are no benefits in the solver. In this case the only improvement will be due to graphics, historian queries and main application loop overhead etc. being processed by the 'other' processor/s.

The tag 'PlantModel.SolverThreadsRequired' in Plant Model 9.2 allows control of Multiprocessor's for use by the network solver. The options are:

  1. Match NoOfProcessors : (Recommended option) SysCAD will use the Threaded Solver and automatically select the number of solver worker threads based on the number of available processors.
  2. Non-threaded Solver : Do NOT use the Threaded Solver.
  3. UserSpecified : The user can specify the number solver worker threads.

What are PGM files?

PGM files are programmable files that allow the user to extend the functionality of the SysCAD models. It is used extensively in SysCAD Dynamic modelling. In Process Balancing mode, the user can use the PGM files to put in simple ratio controls or calculate user-defined variables and so on. See PGM Introduction.

How do I report the graphics window name for a unit?

Using the SysCAD Excel Get Tag Reports, the tag "Graphic" may be used to report the name of the graphics window that the unit is on.

See Excel Tag Select Reports - Special Graphics Field Names for an example of how to do this.

Why do I get a Warning Message "Reference now refers to"?

This message may be displayed if the user has at some point used a variable from a pipe that had a Qi section and the pipe is now a 'simple' pipe, i.e. it only has a Qo section. Unfortunately, unlike controllers, the warning does not specify which functionality is causing the problem.

The culprit may be any of the following:

  1. Trend Windows: Check and clear if the offending tag exists in any of the project Trend windows.
  2. Excel Reports: Check for these messages after generating an Excel report and then find & correct any tags in Excel.
  3. Data Historian: If a tag has been added to the historian at any time (even if it is currently not in a trend page), it can be the cause of the error message. See Delete Historian to delete the list of tags recorded by the historian.
  4. Quick View: Check if the Quick View Configuration has any variables that refer to Qi. If any do exist, remove them and replace them with the equivalent Qo variable. See Quick View for more information.
  5. Animation: Check if an Animation Table, Dynamic Bars or Toggles refer to the Qi variable. If they do, remove them and replace with the Qo variable. See Animation Commands for further information.

Species Related questions

How do I add a new compound to the project?

To add a species to a SysCAD project, first check if the species exists in the project species database. Add it to the database, if necessary, and then add the species to the project Configuration file.

  • For SysCAD 9.3, please see Adding a New Species in the SysCAD 9.3 Database section.
  • This YouTube video shows you how to import a species from the default SysCAD database and how to add data for a new species.
  • This video shows you how to add a species to the Configuration file - Edit the Project Configuration. (It also explains some of the Configuration functionality)

(If you are using SysCAD 9.2 please see Add New Species Manually in the SysCAD 9.2 Database section.)

How can I add 'Bound Water' or Ice to a Project?

Properties for solid H2O - ice or 'bound' water trapped in a solid crystalline structure, are not included in the distributed SysCAD species database. To include a 'solid' form of H2O, add a species in the normal way with the following rules:

  • Name can be anything, such as 'BoundWater', BoundMoisture', etc;
  • The Compound must NOT be 'H2O'. Again use a different word, such as 'Ice', 'BoundH2O', etc;
  • The Definition must NOT be H2O1 - use O1H2;
  • Phase Occurrence will be 'solid';
  • All other fields in the species database can be filled in as required.

How can I increase the Cp temperature range of a Species?

The issue of a species existing in a stream at a temperature slightly above or below its Cp temperature range in the species database occurs quite frequently in projects. We do NOT recommend changing the temperature range for the specific heat (Cp) in the species database – this information is usually obtained from testwork and it is not a good idea to change it in the database.

The best way to change the range is to change it in the configuration file.

With the project closed:

  • Go to ‘Edit – Project Configuration’;
  • Select and edit your project configuration from the dialog box;
  • On the species tab of the configuration editor you can highlight the required species and you can increase the temperature range by changing the value for ‘Tolerance’ in the bottom right hand corner.

For SysCAD 9.3, this is described in detail in the Extending the Temperature Range for Cp in the Configuration File.

In this way you do not change the values for the species that you obtained from your references, but you tell SysCAD that you want to work a little outside of the true range.

I have a user defined species model available, how do I go about changing species models?

If additional species models are available to the user, then the species model can be set.


  1. The DEFAULT species model for the project needs to be set in the models configuration file (.cfg). For more information on the models configuration file, please see What is a configuration file?.
  2. Once the default species model has been set, any new unit operations inserted into SysCAD will carry this species model.
  3. In practice, only feeders and Makeup Sources need to have the species model information defined, if the species model used differs to that of the default. Any other units will use the species model of its inlet streams.
  4. To set the species model in the Feeder or the Makeup Source, under the Contents tab page, select the modeltype. If a species model is selected, then (Reqd) will appear after the word Model as a reminder that the user has manually set the species model. If the user wants to set the species model back to its default, then Inherit should be chosen, when this happens, (heritage) will appear after the word Model as a reminder that the species model is determined by SysCAD.
  5. In the case of two different species model entering the same unit operation, SysCAD will decide what to use for its outlets. In these cases, the user can manually set the species models in the outlet pipes if they prefer to use a different species model.

The SysCAD value for entropy is different to the value from my steam tables/Mollier diagram/IF97 calculations.

For doing steam turbine and compressor calculations all that is needed is the difference in entropy between two states (eg temperature and pressure). So it is common to set the entropy to zero at a particular temperature and pressure, eg atmospheric pressure and 0°C. If you are only ever concerned with steam this is fine.

If however you have more than one species present, then you can't arbitrarily set the entropy for each species to zero at a particular reference temperature and pressure. For example when water evaporates, there is an increase in entropy associated with the phase change, so that the entropy for liquid water will be negative at reference (T, p) where steam has zero entropy, you have to account for the entropy of evaporation just as you have enthalpy of evaporation.

In situations where you have complex reactions, such as combustion modelling with the Free Energy Minimization unit, you need some way to ensure that all the entropy values are calculated with respect to a common reference point. The reference point is chosen to be absolute zero, since at absolute zero the entropy is actually zero (from the statistical rather than thermodynamics approach). The entropy value so calculated is then called the absolute entropy.

Doing calculations from absolute zero is difficult, so the practical approach is to determine the absolute entropy at a more reasonable temperature and use this as the base point for entropy. The reference point chosen is 25°C and atmospheric pressure, and the entropy value S25 can be entered in the species database. For water and steam, the S25 values are built-in, and are 70kJ/kMolK and 188kJ/kMolK at reference conditions. Steam isn't actually a vapor at 25°C, but we can do calculations starting from this reference point by assuming it behaves like an ideal gas.

The IF97 steam model is used internally by SysCAD for accurate steam calculations. However the IF97 reference point is the triple point of water; the entropy (and enthalpy) of liquid water at this point have been set equal to zero and thus the IF97 calculations do not give the absolute entropy. SysCAD corrects the IF97 values by a constant shift to ensure that the values are absolute entropy (and thus match the accepted standard molar entropy values when T=25°C)

In summary, the values calculated and displayed by SysCAD are absolute entropy values; the differences will still be the same when you calculate the change of entropy between two states.

Reactions related questions

How can I recycle a species that is produced to an earlier reaction where it is consumed?

If the user adds a species as a 'Source' in a reaction block, then SysCAD will recycle this species within the reactions.

For example, if H2SO4(aq) is a reactant in Reaction 1, and is then produced in Reaction 5, how can we tell SysCAD that any acid produced in Reaction 5 must be available for use in Reaction 1? If we add a 'Source' to the reaction block and then add H2SO4(aq) to the source, SysCAD will recognise that it must use any acid that is produced in subsequent reactions in earlier reactions.

Please also see Reaction Source.

Why is my Final Conc extent requirement not met?

It is important to remember that reactions are normally solved sequentially in the Reaction Block. Hence, any reaction that has Extent = Final Conc, should be the last reaction in the reaction file. If it is NOT the last reaction, then subsequent reactions may change the liquor density, or amount of the aqueous species, and hence the concentration will no longer be correct.

Please also see Final Concentration.

How can I find the values for mass transfer for individual species in a reaction?

To display the individual mass transfer for all species in a reaction, both reactants and products, go to the 'RB' page and change the 'SpChangeInfo' field to All Species - Mass:


This will then display the mass change for all species for each reaction.

You can also display the molar change for all species by choosing All Species - Molar, or both the mass and molar values with All Species - Both

On the individual reaction pages, make sure that the 'MsChg' group is open, and you can then see the mass (or molar) changes for each species for each individual reaction:


Please also see Display Additional Reaction Information.

Flash Train related questions

See also Configuring and Using Flash Trains for more help on a Flash Train.

Why is the display colour of some models white?

Under Options | General | Colour tab page, the user can select different colours to display the unit operation's status. Generally, when the display colour of a model is white, they are part of a macro model, or a Flash Train model.

What are macro models?

Macro model is the name given to a Flash Train. When models such as Flash Tanks, heat exchanger are correctly connected together, a flash train will be formed. For example, a flash Tank and a shell and tube heat exchanger has formed a Flash Train, these two unit operations will be displayed in white. When models are under the flash train mode, SysCAD calculates the amount of steam being flashed off the flash tank based on the shell and tube exchanger configuration.

For more information see Flash Train.

The LMTD displayed is wrong.

Its not wrong. It is calculated from the condensing temperature of the vapor, rather than the actual terminal temperatures. Here is what is going on - this shows the temperature profiles along the length of the exchanger for the cold and hot sides:


The calculation of heat transfer based on LMTD makes a number of assumptions, for example that that specific heat is constant and that the heat transfer coefficient doesn't vary along the exchanger. In the picture, the hot side profile would roughly follow the dotted line. Based on these assumptions we can determine the temperature profiles and then calculate the net driving force, the LMTD equation:

[math] \Delta T_1 = T_{H_i} - T_{C_o}, \qquad \Delta T_2 = T_{H_o} - T_{C_i} [/math]

[math] \Delta T_{LM} = \frac{\Delta T_1 - \Delta T_2}{\ln \Delta T_1/\Delta T_2} [/math]

In flash train applications, the steam coming off the liquor is superheated because of boiling point elevation, so enters the condenser at a higher temperature than the final condensing temperature. So it must initially be desuperheated over some area of the exchanger, we refer to this as the desuperheating zone. The temperature profile follows the solid line.

In the desuperheating zone, the heat transfer coefficient is much lower than in the condensing zone, though the temperature difference between the steam and the liquor may be higher. These two effects tend to cancel each other out in calculating the overall temperature driving force for heat transfer.

So determining the true LMTD for a desuperheater-condenser is a complicated calculation. In practice it is adequate to calculate the LMTD based on the condensing temperature since the desuperheating zone is small and the two effects (higher temperature split and lower HTC) tend to cancel each other out. If you calculate LMTD based on the actual terminal temperatures, you are effectively adding in additional driving force (the gray area in the figure) and the number you calculate will be too large. The models use the condensing temperature at both terminals:

[math] \Delta T_1 = T_{H_c} - T_{C_o}, \qquad \Delta T_2 = T_{H_c} - T_{C_i} [/math]

In summary, the LMTD displayed in the condenser model is calculated from the liquor terminal temperatures and the vapor condensing temperature and that is a perfectly adequate assumption for basic design. In the real world, you are lucky if you know your heat transfer coefficients to within 20%.

Why is the steam vapour pressure not equal to atmospheric pressure at 100°C?

If you have a saturated steam stream at 100°C you find the pressure is actually 101.418kPa, or 1.0009 atm, which differs from 1atm by one tenth of one percent. Or if you set the pressure to 0barg (1atm), the temperature is not exactly 100°C.

The Celsius scale has been refined over the years from its original incantation, where the freezing point of water was set at 0°C, and the boiling point of water at atmospheric pressure to 100°C. The latest temperature scale defines temperatures at a number of points such as the melting point of gallium and the triple point of hydrogen. The only water value it uses is the triple point of water or 273.16°C. On this new scale, water actually boils at 99.974°C. SysCAD implements the IFS97 steam model, which uses this revised temperature scale.

In practical terms this difference is minute: it would be the difference in boiling point due to an elevation change of about 8 m.

What is the difference between BPE@T and BPE@P

There are two different ways to display Boiling Point Elevation (BPE) - as a function of pressure and as a function of temperature. For saturated liquids the two give identical results, they differ when you have a nonsaturated (subcooled) liquid and only if the boiling point elevation has a temperature dependency as well. The Alumina3 properties model displays both BPE@T and BPE@P.

For a subcooled liquid, we can get to saturation (boiling/flashing) by either

  • Raising the temperature at a fixed pressure
  • Lowering the pressure at a fixed temperature.

The two different BPE displays relate to these two scenarios -- once we reach saturation, either the liquor temperature has changed or the pressure has changed, and because of the temperature dependence of BPE, the liquors are in different thermophysical states and we should expect the properties (including BPE) to be different as well.

For example, suppose you are specifying operating conditions for a charge pump in a digestion system where live steam is used to heat an incoming liquor in a heat exchanger. To avoid boiling in the tubes (with resulting loss of efficiency and possible pitting and damage to heat transfer surfaces), the charge pump is operated at some margin over the liquor vapor pressure. In this case it is the BPE@P which is relevant to the calculation - if BPE@P is ten degrees and we are operating the charge pump at 6MPa, then the liquor boiling point of 285C is immediately determined from the water boiling point of 275C, and we can control live steam flow to provide a suitable margin.

Modelling related questions

I have a number of graphics pages in the project representing different areas in the plant. How do I join the flows between pages?

This is done via the Feeder-Cross Page Connector unit operation, in the Cross Page Connection section, which is located on the first tab page of the Feeder unit operation access window. Simply type in the Tag name of the unit operation (must be another Feeder/Cross Page unit op) to be connected to in the Conn_to field.

Feeder 2.png

NOTE that you can only have one connection made at any one time. Deselecting the ConnectionOn check box can break connections.

For more information on this, please refer to the Cross Page Connector.

Can I select the graphics pages that I want to run?

You can activate and deactivate graphics pages in either of the following ways:

  1. Via the Project - ProBal (Steady State) Setup - Active Pages tab page. To deactivate all pages, select the Plant model option and press the Deactivate button, (or press Activate if you want to reactivate them.) To activate/deactivate individual pages, select them one at a time and press activate/deactivate; or
  2. Via the Explorer Window, by right clicking on the required Graphics name and clicking on Active. See Manipulating Graphics and Trend Windows.

NOTE: When running the pages separately, please make sure all feeders to individual pages are configured properly. NOTE also if these feeders were cross page connected prior to being deactivated, users can use the Composition Fetch option in the access page to get the solved flows. See the next question for more information.

How do I add or remove particle size distribution data from a Stream?

Add Size Distribution Data

You must have already added the size distribution information to the project configuration file (see How do I add particle size distribution data to a project?).

You can then open the project and access the relevant feeder with solids - this is where you will set the size of the solids entering the plant. On the second tab of the Feeder, called ‘Content’, you will see a heading called Qualities. If this has a + box on the left side, click on this and it will show the qualities that you can set in this feeder – one of which is ‘SzDistAct’.

Click on the arrow next to the SzDistAct box and select ‘Create’ from the drop down list.

You will now see that you have quite a few extra tabs visible in the feeder, the first two are Sz and MSz. Go to the Sz tab and you will see that you can now input the size distributions for the solids that you selected in the configuration file.

You will now have size distribution information in all streams with these solids in your project.

Remove Size Distribution Data

There are times when you only need this information at the front end of the project, e.g. for the crushing, screening and milling sections. Thereafter you may not be interested in the size distribution data. You can remove this information in the following way:

Go to the stream where you would like to remove the size distribution information and click on the Qi tab.

Go to Qualities and got to ‘SzDistAct’ and then select ‘Remove’ from the drop down list.

Please also see Common Content Section

What do the coloured triangles displayed on an Access Window mean?

If a value is either controlled or referenced by a control unit in SysCAD, then a coloured triangle will be displayed next to the tag in the Access Window.

If the triangle is directed INTO the value, >, and it is either blue, magenta or red, then the value is being controlled, or Set, by a controller. In this case, the user cannot set the value manually, as it will be overwritten by the controller.

If the triangle is directed OUT of the value, <, and it is green, then the value is referenced, or measured, by a control unit.

The user may right click on the value and the pop-up menu will display the tag of the control unit that is referencing the value. The user can then navigate to the control unit, if required. (See Controlled and Referenced Variables)

How can I add Gland Seal water to a Pump in Steady State Mode?

The Pump 1 model does not allow more than a single input, so this will not allow the user to add Gland Seal water to the Pump. Rather use the Tie model and change the Operating Pressure method to RequiredP. This will allow you to set the required pressure from the 'Pump'

You can then:

  • Add a Makeup Block to the Tie with the required Gland Seal water flow; or
  • Add another feed to the Tie with the Gland Seal water.

How can I configure a Tank or Tie with Phase or Species split to pass 'Demand' correctly?

The Operation mode on the GM tab, MUST be set to General for the unit to pass the Demand from the downstream pipes to upstream pipes.

Please see Passing Demand through a Unit for further information.

How can I set the initial contents of a tank in a Dynamic project?

There are two main ways to set the contents of a tank.

  1. Set the contents directly usually masses and temperature (or level and temperature) on the Content pages of the tank.
  2. Use the Preset functionality on the Settings page. To set the composition, tick the UseImage box and enter the desired composition values on the PresetImg page.

The setting of the desired values (both direct sets and preset settings) can be set in a number of ways:

  1. Using a Set Tag List Model. Either use the SetDuringInit option or use the Set Tag List model in the Plant Model 9.2.
  2. Using a General Controller, inside an OnInitialise if block.
  3. Using an Excel Set Tag Report before running.
  4. Manually setting the values before running.

The Preset functionality can be activated locally or globally by any of the methods described above for setting values described above. In addition, the Preset can be activated globally by going to the Dynamic Start Options and ticking the Preset box. When using the global Preset option, the AllowGlobal box must be ticked on the Settings page of the tank/s in which it is desired to use Preset.


  1. Ensure you are not trying to set the tank contents via two different methods. As well as directly setting the contents of the tank and using the Preset functionality, there is an option to Empty the contents of tanks (check Dynamic Start Options).
  2. Make sure your setting of variables are performed early enough in the initialisation stage. If the Set Tag List Model or General Controller appear to be setting tags too late, then consider using the Set Tag List in the Plant Model 9.2 or methods such as an Excel Set Tag Report which sets the tags prior to running the model.

Mass and Energy Balance related questions

Where can I get information for Mass and Energy Balances?

  • In SysCAD ProBal the operation mode is steady state and therefore no mass accumulation occurs. All Mass and Energy Balance information is provided in the pipe models, i.e. flowrate, temperature, pressure, enthalpy, specific heat, etc. can be found by right clicking on the PIPES.
  • The Audit tab does show a summary of the total input and output mass and energy numbers for individual unit operations. Therefore, to check the energy balance around an individual unit, the user can look in the individual model.
  • The Links tab shows all of the flows into and out of each unit and also shows the change in selected species across the unit due to reactions.

For more information about mass and energy balances, please see section Mass and Energy Balance.

For information about Energy Balance around reactions, please see Reaction Block Energy Balance.

What is the difference between Hs and Hz?

The enthalpy of a species, or stream at Temperature, T, and Pressure, P, is calculated using the specific heats with a reference temperature of 0°C and 101.325kPa.

  1. SysCAD assigns ALL species an Hs value of 0J/mol at 0°C and 101.325kPa.
  2. SysCAD assigns most species an Hz of 0J/mol at 0°C and 101.325kPa.
    • However the exception is species that exist in 2 or more phases, where Hz at 0°C and 101.325kPa is calculated as follows:
    Hz = Energy of Formation at 0°C and 101.325kPa of the species - Energy of Formation at 0°C and 101.325kPa of the species in the 'lowest' energy phase (g > l > s)

Therefore, if the project contains any species that occur in 2 or more phases, the Hs and Hz values will be different by this amount.


A project has NaCl in both the aqueous and solid forms with the following values:
At 0°C and 101.325kPa:
NaCl(s): Hf = -7060kJ/kg Hs = 0kJ/kg Hz = 0kJ/kg
NaCl(aq): Hf = -7000kJ/kg Hs = 0kJ/kg Hz = 60kJ/kg
Therefore, any streams that contain NaCl(aq) will have a difference between the Hs and Hz values of 60kJ per kg of NaCl(aq).

Please see Hs and Hz for information about the display fields.

Graphics related questions

How can I change the Background Colour of my Graphics?

The user may select a different background colour for all of the graphics in a project. Currently the background colours are Black, Dark and Light Grey, Off-White and White. The background colour scheme can be changed in right click popup menu for Graphics in Explorer Window or as described in Graphics Symbols Displaying Colours.

Note: This functionality is only available in SysCAD 9.2.

How can I display all Pipe Tags?

Click on the 'Tag' icon or Graphics - Edit - Tag Position, Show or Hide and then click on the 'Show All Link Tags' button (ensure that the 'Set Tag position' tick box is NOT ticked):

Show all link tags.png

See Tag Position, Show or Hide for more information.

See also Basic Tutorial - Edit Tag Displays for short video showing this functionality.

Where and how are the Graphics Symbols (used for insert unit) stored?

The distributed graphics symbols are stored in the folder \SysCAD92\BaseFiles\Symbols. They are grouped into folders of related symbols, each containing .dxf files for each symbol. The dxf file is the actual drawing file SysCAD uses when inserting the unit when using Insert Unit or Change Symbol. For more information on graphics symbols, please see topic Data Libraries - Graphics Symbols.

Can I create my own Graphics Symbol (used for insert unit)?

A user can create the new symbol following steps outlined in the topic Creating Symbols from within SysCAD.

  • For users using SysCAD 9.2 Build 135.13379 or newer, they can then save the new symbol using the Menu Command Graphics | Symbol Management | List All Unit Symbols - Export Symbol button. See topic Saving the New Graphics Symbol
  • For users using older versions of SysCAD (from Build 134 to Build 135.13379), the command export can export a copy of the graphics symbol for re-use. Please refer to Managing User Created Graphics Symbol for more information.

How do I 'Stretch' a Graphics Symbol?

  1. Activate the 'Scale/Rotate' command, either from the Icon, User Guide image261.jpg, or from the drop-down menu, Graphics - Edit - Scale/Rotate.
  2. Click on the unit that you wish to stretch, and then click on the 'Dialog' button in the Scale/Rotate menu.
  3. Enter the required values in the X and Y boxes (in the example below we have stretched the Tie in the X direction, scale = 10, and squeezed it in the Y direction, scale = 0.3.
  4. Click on the 'Apply' button and if you are happy with the result, click on Accept or Done.
  5. If you are not happy with the result, you may go back to the original symbol by clicking on the Restore button, or you may enter new X and Y scales.

The example below shows a Tie that has been stretched in the X plane and squeezed in the Y plane:

Stretch Graphics Symbol.png

How do I create a Mirror image of a Graphics Symbol?

  1. Activate the 'Scale/Rotate' command, either from the Icon, User Guide image261.jpg, or from the drop-down menu, Graphics - Edit - Scale/Rotate.
  2. Click on the unit for which you wish to create a mirror image, and then click on the 'Dialog' button in the Scale/Rotate menu.
  3. To create a mirror image in the X plane, enter a negative value in the Scale box for X.
  4. Similarly, to create a mirror image in the Y plane, enter a negative value in the Scale box for Y.
  5. Click on the 'Apply' button and if you are happy with the result, click on Accept or Done.
  6. If you are not happy with the result, you may go back to the original symbol by clicking on the Restore button.

The example below shows a mirror image that has been created in the X plane for a Filter Press.

Mirror Graphics Symbol.png

Can I use a Graphics Symbol other than the default set for the unit operation?

Yes, simply choose a different group of symbols from the Group dropdown list.

For SysCAD 9.1, click the All Symbols tick box on the Insert Unit dialog box before inserting the unit operation and you can choose anything from the entire graphics symbol list.

Can I have a drawing border for my flowsheet?

A drawing border will always add to the presentation of the flowsheet. The best way to do this is to add the border as symbol. Use the Insert Symbol function and select the Extras drawing group. Typically an A3 frame should be selected, but you can choose A1/A2/A3/A4FrameSymbol, depending on the Size of the flowsheet.


After the border has been inserted it can be rescaled using the Scale/Rotate function and it can be positioned using Move function.

Please also see Basic Tutorial - Insert a Flowsheet Border, which has a short video describing how to insert a flowsheet border.

How do I align Graphics Symbols on the Flowsheet

Although there is no align Symbol functions in SysCAD, there are a couple of ways to help with placement of graphics symbols:

  1. SysCAD has snap to grid option, set via Options | General | Graphics, use an appropriate grid size to help with major unit operation placement. Recommend a large grid size of 6, 10 or 12 for A3 frames. A grid size of 10 is 10mm when printed on A3 (420 x 297 mm).
  2. Insert a A3Frame_WithRuler symbol along with the chosen A3 frame. Use the "ruler" to help with spacing while drawing the flowsheet. Once the flowsheet is completed, user can choose to remove the A3Frame_WithRuler symbol.

Can I add a title to my flowsheet?

The best way to do this is to use the graphics command Insert Text. If a border is required around the text, simply use the insert symbol function to add a box. (Eg: Group: MixerSplitter - TitleBox, Group Extras: A3FrameSimpleWithTitleBox)

Can I add a table of numbers to my PFD flowsheet?

Technically, yes but it is more common to use Excel for these reports. The function is called Insert Annotation Table. Use Graphics | Animation | Insert Annotation Table to create the table. Use Graphics | Animation | Update Annotation Table to edit the table and Graphics | Animation | Refresh Annotation or Refresh All Annotation to update the numbers during solve as the table is only updated on stop.

Can I copy the graphics page as a bitmap?

This is very easy to do, and there are a number of ways of achieving this:

  1. RIGHT CLICK on the BACKGROUND of the ACTIVE flowsheet in SysCAD and choose Copy Bitmap (it is the last option on the pop up menu). A "Print screen" of the graphics flowsheet window only (see note below) will be copied onto the clipboard.
  2. With the desired flowsheet currently the ACTIVE window, choose Copy Bitmap (it is the second last command). A "Print screen" of the graphics flowsheet window only (see note below) will be copied onto the clipboard.
  3. Right Click on the Graphics name in the SysCAD Explorer window and select 'Copy Bitmap to Clipboard' (also see Explorer Window)

NOTE: This will copy what is on the active graphics page as is. Thus if the graphics page is zoomed into an area, it will only copy that particular section. Also, SysCAD puts this bitmap in mono colour i.e. black lines on white background.

You can paste the bitmap into other applications.

The standard "Print Screen" keyboard key can also be used to copy a full screen colour image to the clipboard.

What do I need to do to import an external drawing?

If you have access to a pre-drawn CAD drawing, whether it was created in AutoCAD, Microstation or Visio (and so on), as long as you can export the drawing to a DXF format, you can import it into SysCAD. However, there are a few things to keep in mind:

  • All blocks on the CAD drawing must be exploded, these include polylines and hatches. In particular, check for blocks that are "Off" and "Locked" - turn on all the layers and deal with any blocks.
  • Any external references must be removed; these will often include any frames used. Frames can exist on the drawing, but only if it is part of the drawing, not as a reference drawing.
  • After all the blocks are exploded, it is best to do a purge on the drawing to remove any unused layers and styles; this will keep the drawing as small as possible.
  • Long text strings and foreign language characters may cause problems

Once you have the DXF drawing ready, create a blank graphics page in SysCAD, use menu option Graphics | Construct | Load Drawing and select the dxf drawing you have created. Check that all the lines and symbol have been imported properly, if not, go back to the other drawing package and fix any unexploded symbols and try again.

How can I manipulate the graphical representation of models?

The simplest and most commonly used commands are Change Symbol for units and Redraw Link for pipes. There are a number of ways to change the graphics symbol associated with a mathematical model or a tag. The point to remember is that when you insert or construct a unit or pipe, you have attached a mathematical model behind some selected graphics of your choice. Therefore, there are two separate components: the Graphics Symbol and the Mathematical Model. These two normally have a 1-to-1 relationship, but you can manipulate SysCAD to change either or both of the components.

Please see Manipulating Graphics for a detailed description of the commands and how they manipulate the graphics and the mathematical models.

Trend Window Questions

Every time I run the project, the trend data restarts. How do I stop this happening?

In the View/Probal Configuration menu item, look on the FS_PB tab. Under Solver Start Actions uncheck SetTimeToZero.

This can be set inadvertantly if you have used a global reset Actions/Reset

How to fix warning "Slots expected in ID sequence"

Sometimes user may get the following message when running the SysCAD project:

Slots expected in ID sequence, OR values for the same time are being sent for "SysCAD Tag"

This is related to the Historian file, to fix the problem, clear and restart the Historian.

To do so, go to Project | Settings | Historian Tab – Press Delete then Restart.

PGM Frequently Asked Questions

How can I find the values for Saturated Steam or Water?

The Species Database Class, SDB, will allow a user to obtain the saturated values for steam or water at a user defined temperature and pressure.

The required syntax is:

  • Water/steam saturated vapour pressure - SDB.SpVapourP(H2OIndex, Temperature). Temperature is in Kelvin.
  • Water/steam saturated temperature - SpVapourT(H2OIndex, Pressure). Pressure is in kPa.

Note: H2OIndex is defined by the user and is the species index of water or steam. Example: H2OIndex = SI("H2O(g)")

Please see Species Database Class Example for a worked example.

What is the difference between GetTag(), SetTag() and GetDynTag() and SetDynTag() and when do you use them?

The difference between GetTag() and GetDynTag(); SetTag and SetDynTag is subtle. It is NOT related to dynamic mode.

  • The GetDynTag() and SetDynTag() functions "dynamically" build the Tag, when required. This can also be a string based on logic using strcat that you want to set/get.
  • At start-up, when you press solve, SysCAD has a list of all tags used in SetTag() and GetTag() which it checks to see if they can ALWAYS be legally set/read.
  • For SetDynTag() and GetDynTag() the checking of the tag is done at runtime when the command is called.

Please also see Keywords, Functions and Classes in the PGM section.

How do I enter an equation of the form y = -x?

The pgm syntax does not allow users to enter the negative form of a function. To convert to negative, multiply by -1, as shown in the examples below:

Required Equation Equation in pgm
y = -x y = -1 * x
y = exp(-x) y = exp(-1 * x)

How do I avoid a 'Divide by Zero' error?

At times a user may get a 'Divide by Zero' error in their general controller or model procedure. This can be caused in a number of ways:

  • When the code uses a variable that has been read in from the SysCAD model, using a GetTag() (or Get()) command, and the measured variable is unexpectedly zero; or
  • The code uses a User defined variable and the user types in zero; or
  • The denominator is the result of a previous calculation which produces a zero value.

It is good practice to ALWAYS ensure that the denominator is not zero when doing a division. The following example shows methods of avoiding a zero denominator when using a measured SysCAD variable as the denominator, but these methods can be used for all of the above cases.

Example: The following two variables are measured in a PGM:

  SolidMassFlow = GetTag("P_001.Qo.SQm (t/h)")
  SlurryMassFlow = GetTag("P_001.Qo.SLQm (t/h)")

The user wishes to find the fraction of solids in the slurry, and therefore wants to divide the solids mass by the mass of slurry. However, if for some unexpected reason there is zero flow in stream P_001, this will produce a 'Divide by Zero' error. You can avoid this in PGM code in a number of ways:

1. Check that the denominator is greater than some small number before carrying out the calculation (You may check that it is greater than zero, but rather choose a reasonable small number, because otherwise you may end up dividing by a number such as 1e-7 and still get silly results)):

  if (SlurryMassFlow > 0.001)
    SolidInSlurryMF = SolidMassFlow / SlurryMassFlow
    SolidInSlurryMF = 0

2. The above code can also be written as follows (it is exactly the same, just really a shorter way of putting it in the code. See IIf Command for a description of the use of the 'iif' command):

    SolidInSlurryMF = iif (SlurryMassFlow > 0.001, SolidMassFlow / SlurryMassFlow, 0)

3. Use the 'Max' command to ensure that you never divide by a very small number:

    SolidInSlurryMF = SolidMassFlow / MAX(SlurryMassFlow, 0.001)

This command will compare the value of 'SlurryMassFlow' and 0.001 and use whichever is the greater value of the two. Therefore, if 'SlurryMassFlow' is zero, or less than 0.001, it will use 0.001 and you will not have an error in your code.

Note: The user could make use of the 'min' or 'range' functions to avoid silly results, but this would not prevent the divide by zero error message.

How do I set values in CheckBoxes and DropDown lists?

SysCAD Access windows have other items apart from numerical values, such as dropdown lists (where you select from a number of items) and checkboxes (which can be on or off)

PGM code can be used to adjust or query these values in the same way as numerical variables are set.


The values for the items in a dropdown list can be seen to the right of the string description. It is convenient to use the Bit type for Checkboxes and the Byte/Long type for dropdown lists.

Bit   isOn{i, Comment("0 - Off, 1 - On")}              ;; A boolean (0 or 1)
Byte  VLEType{i, Comment("1 - Sat Liq, 2 - Sat vap")}  ;; A byte (0-255)
Long  OPMethod *                                       ;; If larger values are required
if (OnInitialise)
   SetTag("XPG_001.VLEquilibrium", VLEType)
   SetTag("X_001.OperatingP.Method", OPMEthod)
   SetTag("XPG_001.Demand.On", isOn)    


Adding a comment to the variable declaration can make the user choices a bit more obvious!