Conversions Table
From SysCAD Documentation
Navigation: User Guide -> Data Libraries -> Conversions Table
Contents |
Introduction
You can edit the Project Conversions Database in two ways:
- The recommended method is to edit the database via SysCAD.
- Go to Edit - Conversion Database and select Project (you can do this with the project either open or closed), or
- Go to Edit - Project Configuration and then click on the Project configuration of interest and then click on the Cnvs DB button. (You can only do this if the project is closed)
- Alternatively if you are familiar with Microsoft Access and the Conversions database, you can edit the data directly in MS Access. You need to take care of SysCAD requirements for data formatting and rules. Also all the default fields in the default tables should be unchanged as SysCAD accesses them when the projects are loaded or saved.
NOTE: You must exit and reload your project (or exit and restart SysCAD) in order to use any changes or additions.
You will see this dialogue window for updating the Conversions database:
Engineering Units Conversion
SysCAD works internally with SI units for all tags and calculation values. For display purposes the values may be displayed in other engineering units. A full list of all the units available are shown in the project window.
The SI units are defined by SysCAD and cannot be changed. All other units within a "family" or group are defined with a scale and offset relative to the SI unit for that family.
The engineering unit information is stored in the Conversions Table in the distributed access database in \BaseFiles\Default.mdb. These are updated and extended from time to time. These are loaded into memory for use when SysCAD is started.
The user can add customised conversions to the Conversions table of the Project SysCAD.mdb database.
NOTE: All engineering units are case sensitive.
Available Dimension / Unit Groups
Dimension types are identified by a conversion abbreviation eg: Qm stands for mass flow; P for pressure. The table below shows all the Dimension (or "Family") groups, SI units and other common groups defined in SysCAD.
See also Conversion_List_Table.
| Dimension/Group | SI Unit | Description |
|---|---|---|
| Accel | m/s^2 | Acceleration |
| Ang | rad | Angle |
| Area | m^2 | Area |
| Assay | Assay Mass per Mass | |
| Bytes | bytes | Memory Size |
| Cnt | # | Count |
| CntRate | #/s | Count Rate |
| Conc | kg/m^3 | Concentration |
| ConcML | kmol/m^3 | Mole Concentration |
| ConcRate | kg/m^3/s | Concentration rate of change |
| Cond | S/m | Conductivity |
| Cp(Ml) | kJ/kmol.C | Specific Heat Mole base |
| Cp(Ms) | kJ/kg.C | Specific Heat Mass base |
| DP | kPa | Pressure difference |
| DPperVol | kPa/m^3/s | Pressure Drop Per Volume Flow |
| dT | K | Change in Temperature |
| dTdt | C/s | Rate of change in Temperature |
| E | kJ | Energy |
| EntRate | Frac.s/kg | Entrainment Rate |
| Frac | Fraction | |
| FracRate | /s | Fraction rate |
| H(Ml) | kJ/kmol | Enthalpy Molar |
| H(Ms) | kJ/kg | Enthalpy Mass |
| H(NV) | kJ/Nm^3 | Enthalpy Normal Volume |
| H(V) | kJ/m^3 | Enthalpy Volume |
| HCap | kJ/dC | Heat Capacity |
| HCapF | kJ/dC/s | Heat Capacity |
| HCond | kW/m.K | Heat Conductivity |
| HTC | kW/m^2.K | Heat Transfer Coefficient |
| Humidity | kg(l)/kg(v) | Specific Humidity |
| I | A | Current |
| KgMl | kmol | Moles |
| KinVisc | m^2/s | Kinematic Viscosity (Stoke) |
| L | m | Length |
| Ldt | m/s | Velocity |
| M | kg | Mass |
| Money | Base | Money in Base |
| MoneyFlow | Base/kg | Money in Base per Unit Mass |
| MoneyMass | Base/s | Money in Base per Unit Time |
| MoneyVol | Base/m3 | Money in Base per Unit Volume |
| MpL | kg/m | Mass Loading |
| NQv | Nm^3/s | Normal Flowrate |
| NVol | Nm^3 | Normal Volume |
| Ohms | Ohms | Resistance |
| P | kPa | Pressure |
| PpS | kPa/s | Pressure Slew Rate |
| pS | /s | Per unit Time |
| Pwr | kJ/s | Power |
| PwrM | W/kg | Specific Power (Power/Mass) |
| Qe | kJ/s | Energy Flow |
| QKgMl | kmol/s | Molar Flow |
| Qm | kg/s | Mass Flow |
| QmSlew | kg/s/s | Mass flow Slewrate |
| Qv | m^3/s | Volumetric Flow |
| QvSlew | m^3/s/s | Volume flow Slewrate |
| Rho | kg/m^3 | Density |
| S(Ml) | kJ/kmol.K | Entropy Molar |
| S(Ms) | kJ/kg.K | Entropy Mass |
| SpCnt | #/kg | Specific Count |
| SurfAreaL | m^2/L | Surface Area (Volume) |
| SurfAreaM | m^2/g | Surface Area (Mass) |
| SurfTens | N/m | Surface Tension |
| T | dK | Temperature |
| ThermDiff | m^2/s | Thermal Diffusivity |
| ThermTau | dC/s.C | Thermal Time Constant |
| Time | s | Time |
| UA | kW/K | Heat Transfer |
| V | V | Potential Diff |
| Visc | Ns/m^2 | Viscosity |
| Vol | m^3 | Volume |
| WI | kWs/kg | Work Index |
Conversion Factors
Introduced in SysCAD 9.2, for many of the SI conversion groups, there are some hard-wired conversions. If these conversions are defined in the table with the same scale and offset, they are ignored. If they are defined in the table with a different scale and/or offset then they are ignored an error message is given.
Key conversion factors used in SysCAD include:
| Factor | From | To |
|---|---|---|
| +273.15(offset) | Celsius (C) | Kelvin (K) |
| +459.67(offset) 5/9(scale) | Fahrenheit (F) | Kelvin (K) |
| 0.4535924 | pound (lb) | kilogram (kg) |
| 0.9144 | yard (yd) | meter (m) |
| 0.3048 | foot (ft) | meter (m) |
| 0.0254 | inch (in) | meter (m) |
| 4046.8564224 | international acre (acre) | square meters (m^2) |
| 4.1840 | Thermochemical Calorie (cal) | Joule (J) |
| 1054.350 | Thermochemical BTU (BTU) | Joule (J) |
| 6.894757 | Pound per Square Inch (psi) | kilopascals (kPa) |
Conversion Table format:
Conversion
This contains the Conversion abbreviation for the dimensions. For example, all mass flow rates would have the abbreviation Qm.
No new dimension is allowed. The dimension or unit group is specified in the SysCAD coding. When adding new units, they must be added to an existing group.
Unit
This is the unit display label. This is case sensitive. When a new unit is added, it must belong to an existing dimension or unit group.
Scale
If the unit is a SI unit this column is blank.
If the unit is not a SI Unit the column contains the Scale factor required to convert the SI unit to the specified unit.
Offset
If the unit is a SI unit this column is blank.
If the unit is not a SI Unit the column contains the Offset factor required to convert the SI unit to the specified unit according to the following equation:
New Unit = SI Unit * Scale (if required) + Offset
NOTES:
- The SI unit is defined in the SysCAD coding. The units marked SI Unit() are ignored and are presented here for your information only. The SI Units can not be altered from this file.
- In SysCAD 9.1 and earlier versions, Scale and Offset were specified in a single column, ScaleOffset and the user would specify the string "SclOff(Scale,Offset)" where Scale and Offset are the factors required to convert the SI unit to the required unit according to the following equation:
- New Unit = SI Unit * Scale + Offset
Description
This column is not used by SysCAD. It is there for your information only.
Reference
This column is not used by SysCAD. It is there for your information only.
Examples
| Conversion | Unit | Scale | Offset | Description | Reference
|
| Ldt | m/d | 0.000011574 | 0 | metres per day (1 m/s (SI unit) = m/d * 0.000011574) | AN Other 2/7/2008 |
| M | Mt | 0.000001 | 0 | Megatonnes (1 kg (SI unit) = Mt * 0.000001) | T Meting 6/7/2007 |
| Money | $ | 1 | 0 | Dollars (1 Base (SI unit) = $ * 1) | J Doe 12/5/2008 |
| Qm | oz/s | 32.1505 | 0 | troy ounce per second (1 kg/s (SI unit) = oz/s * 32.1505) | T Meting 6/7/2007 |
| Qv | ML/d | 86.4 | 0 | Megaliters per day (1 m3/s (SI unit) = ML * 86.4) | J Doe 12/5/2008 |
