Electrical Design Software | Elecdes Design Suite by Scada Systems Ltd

Multi-Terminal Device symbols


Multi-Terminal Devices (MTDs) are user created composite symbols.

Multi-Terminal Devices are provided, within Elecdes, to be used when a symbol requires more than the standard six terminals allowed in a device symbol or for multiple subcomponent devices that would be better represented as one symbol. MTDs are usually constructed as a box containing all of the required terminals of a device, a tag block and some internal graphical information.

Some examples of devices that are suitable for creation as MTDs are:

  • Selector switches, where the layout of the symbol depends on the user's requirements.

  • A complete relay required to be drawn as one symbol i.e. all of the coils and all of the contacts are shown grouped together.

  • A power filtering device, where the details of the internals of the device are not required.

  • Any device that does not have a standard Elecdes terminal layout.

Multi-Terminal Device Symbol Components

An MTD symbol is a nested block. The symbol is exploded after insertion.

MTD symbols contain:

  • A number of specially named Elecdes terminal symbols.

  • An MTD tag symbol

  • Various graphical elements such as lines arcs and circles.

Specially named discrete terminal symbols are used to represent the device terminals. These terminal symbols are named HTTERMP and VTTERMP. Each terminal is treated as a discrete terminal during an Elecdes interconnection analysis. These terminals do not appear in a bill of materials report but you can cross-reference the MTD terminals. Refer to Ebase for more information on reporting.

The MTD tag symbols, HIMTDT.DWG or VIMTDT.DWG, have the standard device attribute set and minimal graphical information. These blocks hold the information required for reporting i.e. the catalog specification and naming attributes for the MTD. The tag symbols are found in the following directories <EDS>\IMP_SCHE and <EDS>\MET_SCHE (for metric users). These symbols appear to Elecdes as standard device symbols once inserted.

All elements contained in an MTD, excluding the tag and terminals, are grouped as an internal block by the MTD Creation/Editing functions. This block is known as the "graphical elements block".

Symbol File names

You may use any file name for MTD symbols that is not recognised as an Elecdes component symbol.

Elecdes Symbol Naming Conventions

MTD Directory

MTD Symbols are stored in the <EDS>\IMP_GMTD and <EDS>\MET_GMTD (for metric users) directories.

The MTD directories can have subdirectories to assist with your library organisation. Elecdes will search all of the subdirectories for an MTD symbol when it is required for insertion.

Location on the Menu

Multi-Terminal Device symbols can be inserted by selecting the menu item Elecdes > Symbols > Multi-Term Device symbols.

Multi-Terminal Device Creation/Editing is accessed through the Elecdes > Create/Edit Multi-Term Devices menu item.

Insertion Procedure

How to Insert a Multi-Terminal Device symbol

Attributes of Multi-Terminal Device symbols

The tag symbol, HIMTDT.DWG or VIMTDT.DWG, contains the reporting information within a standard set of Elecdes device symbol attributes. The attributes are primarily used for Bill of materials and cross-reference reporting (see Ebase).

The T1 attribute of the tag symbol is reserved for retaining the original block name of the MTD symbol after it has been inserted and exploded. The other terminal attributes of the MTD tag symbol are unused and should remain blank.

The special terminal symbols used for MTDs have the standard attributes of an Elecdes terminal symbol. None of the manufacturer information is required for these terminals. The terminal number attribute, T1, is set, to the user terminal identification, when the MTD device is created and remains unchanged when the device is inserted. The TBLOCK attribute is set to the tagname given to the device upon insertion. These attributes are used during interconnection reporting, to show the MTD tagname and terminal number, for conductor terminations on the MTD.

The graphical elements (lines, arcs, and circles, in the MTD) block contains no attributes.

See also Attributes of Symbols.

Creating and Editing Multi-Terminal Device symbols

For more information about creating and editing Multi-Terminal Device symbols re. MTD Creation/Editing.

Customisation of MTD components and menu entry

For more information on the customisation of MTD symbols and the customisation of their menu entries see Symbol Modification.