Audit
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Navigation: Models ➔ Common Sections ➔ Audit
| Model Tab | Optional Input Content Tabs | Optional Material Content Tabs | Optional Material Flow Tabs | Common Tabs | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| UnitType | Content Section | DSp Section | Content | Sp | EC | Qo | Sp | EC | Info | Links | Audit |
Related Links: Tolerance Testing
This page is for Build 139 or later. For Build 138 or earlier, please see Audit in 138.
Introduction
The details and values on the Audit tab page are only created after the SysCAD Solver has been started. It displays a summary of information related to mass and energy balance calculations for the unit operation. This functionality can be enabled or disabled using the global Audit Options displayed at the top of each Audit page as well as on the Audit Tab Page of the Plant Model. If this is not required then this can be switched off which will provide a small improvement in solver speed.
The Audit checks and warnings on mass and energy balance are independent of solver convergence settings and tolerances. The Audit calculation and functionality is a separate safety check on the solver for conservation of mass and energy in unit models. The tolerances used for these checks are AuditCheck.MassTol and AuditCheck.HeatTol which are visible on the Audit tab page for Plant Model as well as the Audit tab page for each unit model. The usual Tolerance Testing calculation method used to determine if there is an error and if warning messages should be given. When the calculated Normalised Relative Error is < 1 then the unit model is considered to have achieved a mass and energy balance.
Options
These are global settings. They can be set in any unit or on the Plant Model - Audit page.
| Tag (Long/Short) | Input / Calc | Description |
| Options... | ||
| Audit.On | Tickbox | Switch the Total Mass and Energy Audit calculations on or off. If off, no Total Audit calculations will be performed or displayed. This option is for debugging and is always unticked on project load. |
| ElemAudit.On | Tickbox | Switch the Elemental Audit calculations on or off. If off, no Elemental Audit calculations will be performed. |
| AuditCheck.MassTol.Rel | Display | Relative tolerance for mass balance checks. |
| AuditCheck.MassTol.Abs | Display | Absolute tolerance for mass balance checks. |
| AuditCheck.HeatTol.Rel | Display | Relative tolerance for energy (heat) balance checks. |
| AuditCheck.HeatTol.Abs | Display | Absolute tolerance for energy (heat) balance checks. |
| Frequency This setting determines when the Audit tests are performed. |
EveryIteration | Only available in a steady state project. Audit calculations are carried out at every iteration. |
| EveryStep | Only available in a dynamic project. Audit calculations are carried out at every step. | |
| WhenSolved | Only available in a steady state project. Audit calculations will only be carried out when the project is solved. | |
| WhenPausedOrSolved | Audit calculations will only be carried out when the solver is not busy, i.e. when the model is paused or stopped. | |
| ------ | ||
| Basics.ShowExtra | Tickbox | Only visible if Audit.On is enabled. Show Extended Audit Details on the Audit tab. |
| Streams.Collect | Tickbox | Only visible if Audit.On is enabled. Show Streams Audit Summary table on the Audit tab. |
| Elements.Collect | Tickbox | Only visible if Audit.On is enabled. Collect and show Elemental Audit Table on the AuditEl tab. |
| Elements.ShowExtra | Tickbox | Only visible if Elements.Collect is enabled. Show additional columns in the Elemental Audit Table on the AuditEl tab. |
| Species.Collect | Tickbox | Only visible if Audit.On is enabled. Collect and show Species Audit Table on the AuditSp tab. |
| Species.ShowExtra | Tickbox | Only visible if Species.Collect is enabled. Show additional columns in the Species Audit Table on the AuditSp tab. |
| Messages.OnError | Tickbox | Only visible if Audit.On and/or ElemAudit.On is enabled. Report audit errors to Messages Log in addition to Conditions window. |
| Pause.OnMassError | Tickbox | Only visible if Audit.On is enabled. Pause model if a mass balance error occurs. This option is for debugging and is always unticked on project load. |
| Pause.OnElemMassError | Tickbox | Only visible if ElemAudit.On is enabled. Pause model if an elemental mass balance error occurs. This option is for debugging and is always unticked on project load. |
| Pause.OnHeatError | Tickbox | Only visible if Audit.On is enabled. Pause model if a heat (energy) balance error occurs. This option is for debugging and is always unticked on project load. |
| Elements.DisplayTol.Rel | Input | Only visible if ElemAudit.On is enabled. Relative display tolerance for elemental mass imbalances. |
Basic Audit
This table is only displayed if Audit.On is ticked.
| Tag (Long/Short) | Description |
|---|---|
| Basic Audit | |
| Basics... | |
| Mass.TotalIn (M1) | Mass flow in, including from Makeup Blocks and Reaction Block Sources. |
| Mass.TotalOut (M2) | Mass flow out, including via Discard Blocks and Reaction Block Sinks. |
| Mass.AccumRate (M3) | Only visible in dynamic projects. Change in contents reported as an equivalent mass flow to/from content (surge). |
| Mass.Error | Overall mass error (imbalance). For steady-state projects, = M2-M1. For dynamic projects, = (M2+M3) - M. |
| Mass.NormRelError | Available from Build 139.34853. Normalised Relative Error for mass using tolerance values AuditCheck.MassTol.Rel and AuditCheck.MassTol.Abs. If this value is >= 1 then the audit mass balance test has failed and the result is shown in a red colour. |
| Mass.RelError | Overall relative mass error. This is the Normalised Relative Error multiplied by the Relative Tolerance (AuditCheck.MassTol.Rel). If the audit mass balance test has failed and the result is shown in a red colour. |
| ------ | |
| TotalHeat.In (H1) | Total Heat (Hf) flowing in, including sources. |
| TotalHeat.Other (H2) | Net Total Heat (Hf) Gain in Unit Model including Sub-models (RHX, HOR Override difference, EHX, etc.). |
| TotalHeat.Out (H3) | Total Heat (Hf) flowing out, including sinks. |
| TotalHeat.AccumRate (H4) | Only visible in dynamic projects. Change in contents reported as an equivalent Hf flow to/from content (surge). |
| TotalHeat.Change | Total Heat (Hf) Change, = H3-H1. This will normally be zero if:
If any of the above scenarios are true, then this value will not be zero. |
| TotalHeat.Error | Overall Total Heat (Hf) error / imbalance. For steady-state projects, = H3 - (H1+H2). For dynamic projects, = (H3+H4) - (H1+H2). |
| TotalHeat.NormRelError | Available from Build 139.34853. Normalised Relative Error for Total Heat (Hf) using tolerance values AuditCheck.HeatTol.Rel and AuditCheck.HeatTol.Abs. If this value is >= 1 then the audit energy balance test has failed and the result is shown in a red colour. |
| TotalHeat.RelError | Overall relative Total Heat (Hf) error. This is the Normalised Relative Error multiplied by the Relative Tolerance (AuditCheck.HeatTol.Rel). If the audit energy balance test has failed and the result is shown in a red colour. |
Extended Audit Details
This table is only displayed if Audit.On and Basics.ShowExtra are ticked.
| Tag (Long/Short) | Description |
|---|---|
| Extended Audit Details | |
| Details... | |
| PowerIn (P1) | Heat flow from External Heat Source. |
| PowerIn.RB (P2) | Heat flow from External Heat Source in Reaction Block. |
| PowerIn.EHX (P3) | Heat flow from External Heat Source in Environmental Heat Exchanger (EHX) sub-model. |
| PowerIn.T_Change (P4) | Heat flow from External Heat Source used to control temperature in Makeup Blocks, Evaporation Block (Evap) or Split Thermal (SplitT) option. |
| PowerIn.Total | Total heat flow from all sources, =P1+P2+P3+P4. |
| SensibleHeat.In (S1) | Sensible Heat (Hs) flowing in. |
| SensibleHeat.Out (S2) | Sensible Heat (Hs) flowing out. |
| SensibleHeat.Change | Sensible Heat (Hs) change, S2-S1. This includes HOR from standard reactions (without HOR override). |
| HOD.(Compound)@0.Nett | Heat of Dilution due to compound @ 0°C and Reference pressure of 101.325kPa. This is for the change in concentration for the common flow between the input and output streams (i.e. minimum flowrate of inputs sum and outputs sum). |
Basic Element Audit
This table is only displayed if ElemAudit.On is ticked.
| Tag (Long/Short) | Description |
|---|---|
| Basic Element Audit | |
| ElBasics... | |
| Mass.Error | Overall mass error (imbalance), (mass of elements out) - (mass of elements in). |
| Mass.NormRelError | Available from Build 139.34853. Normalised Relative Error for elemental mass using tolerance values AuditCheck.MassTol.Rel and AuditCheck.MassTol.Abs. If this value is >= 1 then the audit mass balance test has failed and the result is shown in a red colour. |
| Mass.RelError | Overall relative mass error. This is the Normalised Relative Error multiplied by the Relative Tolerance (AuditCheck.MassTol.Rel). If the audit mass balance test has failed and the result is shown in a red colour. |
Streams Audit Summary
This table is only displayed if Audit.On and Streams.Collect are ticked.
In the following table, next to each of the following fields there will be up to four columns. The columns are:
- Qm: The total mass flow in the current iteration/step.
- Mt: Total accumulated mass since the project was last restarted, only visible in a Dynamic project.
- Hf: The Total Enthalpy of all species in the current iteration/step.
- TotalHf: Total accumulated Enthalpy since the project was last restarted, only visible in a Dynamic project.
| Tag (Long/Short) | Description | |
|---|---|---|
| Streams Audit Summary | ||
| Src (Source Material and Energy Entering Project) | ||
| Sources | Material/energy which has been added: - via a Reaction Block Source or Reaction Heat Exchange - if the unit is a Feeder, then this is the amount of material/energy delivered by the Feeder. (Note, a Feeder is a true source of material to the project, unlike a cross page connector which moves material from one flowsheet to another.) - if the unit is a Makeup Source, then this is the amount of material/energy delivered by the Makeup Source. Also includes energy added via sub-models such as Environmental Heat Exchanger (EHX) block. | |
| In (Links In) | ||
| PipesIn | Material/energy which has entered the unit via a link (pipe). | |
| Makeups | Material/energy which has been added via a Makeup Block. | |
| FromDiscards | Material/energy which has been originated from a Discard Block. This is relevant for Discard Sink models. | |
| Out (Links Out) | ||
| PipesOut | Material/energy which has left the unit via a link (pipe). | |
| ToMakeups | Material/energy which has been sent to a Makeup Block. This is relevant for Makeup Source models. | |
| Discards | Material/energy which has been removed via a Discard Block. | |
| Spills | Material/energy which has been spilt. This is only visible in a dynamic project. | |
| Vents | Material/energy which has been vented. This is only visible in a dynamic project. | |
| Snk (Sink Material and Energy Leaving Project) | ||
| Sinks | Material/energy which has been removed: - via a Reaction Block Sink - if the unit is a Sink, then this is the amount of material/energy removed by the Sink. (Note, a Sink is a true sink of material from the project, unlike a cross page connector which moves material from one flowsheet to another.) - if the unit is a Discard Sink, then this is the amount of material/energy removed by the Discard Sink. Also includes energy removed via sub-models such as Environmental Heat Exchanger (EHX) block. | |
| Audit------------ | ||
| TotalIn | The Total of all inputs = Sources + PipesIn + Makeups + FromDiscards | |
| TotalOut | The Total of all outputs = PipesOut + ToMakeups + Discards + Spills + Vents + Sinks | |
| TotalNett | TotalOut - TotalIn. | |
| Accumulation | This is only visible in a dynamic project. The net increase or decrease in material/energy due to change in content (surge). | |
| Error | The absolute error. For a steady state project, this will be the same as TotalNett. For a dynamic project this will be TotalOut + Accumulation - TotalIn. | |
| NormRelError | Normalised Relative Error for streams mass balance using tolerance values AuditCheck.MassTol.Rel and AuditCheck.MassTol.Abs. If this value is >= 1 then the audit streams mass balance test has failed. Before Build 139.34853 this tag was RelError. | |
Elemental Audit
The following parameters and table are only displayed if Audit.On and Elements.Collect are ticked OR if ElemAudit.On is ticked. These will be shown on the AuditEl tab page.
| Tag (Long/Short) | Input / Calc | Description |
| Zeros |   |
Toggle between displaying all elements (even if ZERO flow) or only those with non-zero flow in the Audit Element Flows table below. |
| Options.Elements.ShowExtra | Tickbox | Only displayed if Audit.On and Elements.Collect are ticked. Show additional columns in the Audit Element Flows table below. Also shown on the Audit tab page. |
| Elements.DisplayTol.Rel | Input | Relative display tolerance for elemental mass imbalances. Also shown on the Audit tab page. |
| Audit Element Flows | ||
| ElFlows... | ||
| (The following table will contain one row for each element in the project. The columns shown for each element are described below:) | ||
| Src | Display | Only shown if the Options.Elements.ShowExtra option is ticked. Material which has been added via a reaction source, or if the unit is a Feeder then this is the amount of material delivered by the Feeder. |
| In | Display | Only shown if the Options.Elements.ShowExtra option is ticked. Material which has entered the unit. |
| Out | Display | Only shown if the Options.Elements.ShowExtra option is ticked. Material which has left the unit. |
| Snk | Display | Only shown if the Options.Elements.ShowExtra option is ticked. Material which has been removed via a reaction sink, or if the unit is a Sink then this is the amount of material removed via the Sink. |
| TotalIn | Display | Total material added to the unit. |
| TotalOut | Display | Total material leaving the unit. |
| AccumRate | Display | Only shown in a dynamic project. The change in material due to accumulation or depletion of content (surge). |
| Error | Display | The absolute elemental error. For a steady state project, this will be TotalOut - TotalIn. For a dynamic project this will be TotalOut + AccumRate - TotalIn. |
| NormRelError | Display | Available from Build 139.34853. Only shown if the Options.Elements.ShowExtra option is ticked. Normalised Relative Error for element mass using tolerance values AuditCheck.MassTol.Rel and AuditCheck.MassTol.Abs. If this value is >= 1 then the audit mass balance test has failed. |
| RelError | Display | The relative elemental error. This is the Normalised Relative Error multiplied by the Relative Tolerance (AuditCheck.MassTol.Rel). |
| (The following table is only visible in a dynamic project) | ||
| Audit Element Content | ||
| ElContent... | ||
| (The following table will contain one row for each element in the project. The columns shown for each element are described below:) | ||
| Accumulation | Display | The amount of material which has been accumulated in the content (surge) of the unit. |
| Depletion | Display | The amount of material which has been removed from the content (surge) of the unit. |
| (The following table is only shown if ElemAudit.On is ticked) | ||
| Basic Element Audit | ||
| ElBasics... | ||
| Mass.Error | Display | Overall mass error (imbalance), (mass of elements out) - (mass of elements in). |
| Mass.NormRelError | Display | Available from Build 139.34853. Normalised Relative Error for element mass using tolerance values AuditCheck.MassTol.Rel and AuditCheck.MassTol.Abs. If this value is >= 1 then the audit mass balance test has failed. |
| Mass.RelError | Display | Overall relative mass error. This is the Normalised Relative Error multiplied by the Relative Tolerance (AuditCheck.MassTol.Rel). |
Species Audit
The following parameters and table are only displayed if Audit.On and Species.Collect are ticked. These will be shown on the AuditSp tab page.
| Tag (Long/Short) | Input / Calc | Description |
| SpeciesTag |   |
Toggle between displaying Species names as the chemical compound (short name), or the longer species names, in the Audit Species Flows table below. Refer to Species Long or Short Display Button for more information. Note: This button is independent of the 'Tag:Long or Short' button that is used to toggle the field names on other pages of the Access window between the long and short forms. |
| Zeros | |
Toggle between displaying all species (even if ZERO flow) or only those with non-zero flow in the Audit Species Flows table below. |
| Options.Species.ShowExtra | Tickbox | Show additional columns in the Audit Species Flows table below. Also shown on the Audit tab page. |
| Audit Species Flows | ||
| SpFlows... | ||
| (The following table will contain one row for each species in the project. The columns shown for each species are described below:) | ||
| Src | Display | Only shown if the Options.Species.ShowExtra option is ticked. Material which has been added via a reaction source, or if the unit is a Feeder then this is the amount of material delivered by the Feeder. |
| In | Display | Only shown if the Options.Species.ShowExtra option is ticked. Material which has entered the unit. |
| Out | Display | Only shown if the Options.Species.ShowExtra option is ticked. Material which has left the unit. |
| Snk | Display | Only shown if the Options.Species.ShowExtra option is ticked. Material which has been removed via a reaction sink, or if the unit is a Sink then this is the amount of material removed via the Sink. |
| TotalIn | Display | Total material added to the unit. |
| TotalOut | Display | Total material leaving the unit. |
| TotalNett | Display | TotalOut - TotalIn. |
| AccumRate | Display | Only shown in a dynamic project. The change in material due to accumulation or depletion of content (surge). |
| (The following table is only visible in a dynamic project) | ||
| Audit Species Content | ||
| SpContent... | ||
| (The following table will contain one row for each species in the project. The columns shown for each species are described below:) | ||
| Accumulation | Display | The amount of material which has been accumulated in the content (surge) of the unit. |
| Depletion | Display | The amount of material which has been removed from the content (surge) of the unit. |