Conversions Table

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Navigation: User Guide ➔ Edit ➔ Conversions ➔ Conversions Table

Conversions Conversions Table Conversion List Table

Introduction

There are three locations where the Engineering Units (conversions) are saved:

  1. Inside the SysCAD Program, most of the SysCAD engineering units are hardwired into the SysCAD program.
    • These hardwired engineering units cannot be changed by the user.
    • Engineering units added to this "hard-wired" list are available to ALL SysCAD Users.
  2. User specific conversion database, located in C:\SysCADxxx\BaseFilesUser\"Conversions.db3".
    • This is accessed by using "Edit" - "Conversions" - "Conversion Database"
    • Engineering Units added to this file is available to the specific user on a local machine.
    • If the project is opened on another computer, the "user specific" engineering units may not be available or the same conversion unit may not be using the same conversion factor.
  3. Project Specific conversion database, located in C:\SysCADxxx\ProjectGroup\CfgFiles\"SysCAD.93.db3".
    • This is accessed by using "Edit" - "Conversions" - "Project Database"
    • Engineering Units added to this file is available to all the projects under the same "ProjectGroup" and using the same "SysCAD.93.db3" file (as shown in the above project path)
    • The "CfgFiles" and "Project" can be shared with other users, as long as these files are available together, the "project specific" engineering units will be available.
    • Other project groups (not using the same SysCAD.93.db3 file with user defined engineering units) will not have these "project specific" engineering units. They will need to be re-entered manually.

Adding User Defined Engineering Unit to SysCAD

You can edit the Project Conversions Database in two ways:

  1. The recommended method is to edit the database via SysCAD.
    • Go to Edit - Conversions - Project Database and select SysCAD.93.db3 (you can do this with the project either open or closed),
    • Press "New" to add in a new engineering unit.
    • Please refer to Available Dimension / Unit Groups or Conversion List Table for Engineering Unit groups names and SI units (so you can workout the scale factor and offset).
    • Using the reference table (link given above), fill in the form, then press "Update" to finish. Please see Conversion Table format for more information on the various fields of the table.
    • Press "Done" when you have finished adding all the conversions.
    • You must exit SysCAD, restart and reload your project before any changes or additions are available in your project.
    • Example dialogue window for updating the SysCAD.93.db3, project database:
    ConversiondB138.PNG
  2. Alternatively if you are familiar with SQL databases and the Conversions database, you can edit the data directly in an SQL editor.
    • You need to take care of SysCAD requirements for data formatting and rules.
    ConversiondB138 sql.PNG

NOTES:

  • All engineering units are CASE sensitive.
  • Most of the engineering unit information is hardwired in SysCAD
  • User added conversions will be loaded into memory for use when SysCAD is started.
  • If the user wishes to add a new conversion unit that is commonly used, please send an email to support@syscad.net and we will likely add this to the hardwired list of conversion units within SysCAD.

Viewing the User Defined Engineering Unit in SysCAD

The available engineering units can be viewed in two ways:

  1. View | Conversions - This opens the Project Window, the conversions tab shows all the Engineering Units available. Please NOTE that if you close the Project Window, you are closing the project, so just minimise the window when you are done, do not close it.
    • The user added conversions will be marked with:(DB), as shown in the following picture.
    ViewConversions.png
  2. Edit | Conversions | Defaults and Display

Conversion Factors

  • SysCAD works internally with consistent, usually 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 internal 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.
  • All engineering units are CASE sensitive.

Note:

  • Most of the conversions used in SysCAD are hard-wired.
  • 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 and an error message is given.

Key conversion factors used in SysCAD are shown in the table below:

To Convert from To Use Factor
Celsius (C) Kelvin (K) +273.15(offset)
Fahrenheit (F) Kelvin (K) +459.67(offset) 5/9(scale)
international yard (yd) meter (m) 0.9144
international foot (ft) meter (m) 0.3048
international inch (in) meter (m) 0.0254
international acre (acre) square meters (m^2) 4046.8564224
Thermochemical Calorie (cal) Joule (J) 4.1840
Thermochemical BTU (BTU) Joule (J) 1054.350
avoirdupois pound (lb) kilogram (kg) 0.4535924
avoirdupois pound (lb) Short Ton (ST) 2000
troy or apothecary ounce (oz) kilogram (kg) 0.03110348
Pound per Square Inch (psi) kilopascals (kPa) 6.894757
conventional millimeter of mercury (mmHg) kilopascals (kPa) 0.1333224
US gallon (gal) cubic meters (m^3) 0.003785412
US 42gallon barrel (bbl) cubic meters (m^3) 0.1589873

These factors are from NIST: Guide for the Use of the International System of Units (SI); NIST Special Publication 811 2008 Edition; Ambler Thompson and Barry N. Taylor).

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 some of the commonly used Dimension (or "Family") groups and their units (usually SI). For the complete list of conversions used in SysCAD, please see Conversion List Table.

Dimension Family SI Unit Description
Area m^2 Area
Conc g/L Mass Concentration
ConcMl kmol/m^3 Mole Concentration
Cp(Ml) kJ/kmol.C Specific Heat (Mole basis)
Cp(Ms) kJ/kg.C Specific Heat (Mass base)
DP kPa Pressure difference
dT K Change in Temperature
Frac Fraction
H(Ml) kJ/kmol Enthalpy (Mole Basis)
H(Ms) kJ/kg Enthalpy (Mass Basis)
HTC kW/m^2.K Heat Transfer Coefficient
L m Length
Ldt m/s Velocity
M kg Mass
MRatio g/kg Mass Ratio
MolRatio mol/mol Mole Ratio
Money $ Money in Base
MoneyMass $/kg Money in Base per unit Mass
MoneyFlow $/s Money in Base per unit time
 
Dimension Family SI Unit Description
MoneyVol $/m^3 Money in Base per unit Volume
P kPa Pressure
Pwr kJ/s Power
Qe kJ/s Energy Flow
QKgMl kmol/s Mole Flow
Qm kg/s Mass Flow
Qv m^3/s Volumetric Flow
Rho kg/m^3 Density
S(Ml) kJ/kmol.K Entropy (Mole Basis)
S(Ms) kJ/kg.K Entropy (Mass Basis)
SurfAreaL m^2/L Surface Area (Volume)
SurfAreaM m^2/g Surface Area (Mass)
T dK Temperature
Time s Time
UA kW/K Heat Transfer
Visc Ns/m^2 Viscosity
Vol m^3 Volume
WI kWs/kg Work Index
 

Conversion Table format:

Family

This contains the Conversion abbreviation and description for the dimensions. For example, all mass flow rates belong to the family Qm: Mass Flow.

No new families are allowed. The dimension family 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 family.

Method

There are three options:

1) SI Unit - the unit is the SI unit for this dimension family.

2) Scale and Offset - the user will specify a scale and offset of this unit relative to the SI unit for this dimension family.

3) Gauge Pressure - the user will specify a scale of this unit relative to the SI unit of kPa for the pressure family. The offset will be calculated by SysCAD with reference to the user specified elevation on the Environment tab page of the Plant Model.

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 an SI unit or a gauge pressure then this column is blank.

If the unit is has a Scale and Offset then 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:

  1. 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.

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.

Loading the modified data into SysCAD

You must exit and reload your project (or exit and restart SysCAD) before any changes or additions are available in your project.

If the project is opened when conversion data is modified, user can select an option from the popup dialog box to save/close/reload the project.

The popup dialog box may look like this when SysCAD detects a change in the conversion database:

SaveAndReload.PNG

User can choose to save and reload the project to use the most up to date information or one of the other options.

Examples

Family
Unit
Method
Scale
Offset
Description
Reference
Ldt: Velocity m/d Scale & Offset 0.000011574 0 metres per day (1 m/s (SI unit) = m/d * 0.000011574) AN Other 2/7/2008
M: Mass Mt Scale & Offset 0.000001 0 Megatonnes (1 kg (SI unit) = Mt * 0.000001) T Meting 6/7/2007
Money: Money in Base $ Scale & Offset 1 0 Dollars (1 Base (SI unit) = $ * 1) J Doe 12/5/2008
Qm: Mass Flow oz/s Scale & Offset 32.1505 0 troy ounce per second (1 kg/s (SI unit) = oz/s * 32.1505) T Meting 6/7/2007
Qv: Volumetric Flow ML/d Scale & Offset 86.4 0 Megaliters per day (1 m3/s (SI unit) = ML * 86.4) J Doe 12/5/2008
P: Pressure barg Gauge Pressure 0.01 gauge pressure in bar (1 kPa (SI unit) = barg * 0.01 + AP), where AP = atmospheric pressure in kPa J Doe 12/5/2008