EPLAN Electric P8: project structure, macros and the parts database

The short answer

EPLAN pays for itself through three things, and drawing is not one of them. First, a project structure built on IEC 81346 designations, so every function, location and device has an address the whole documentation set agrees on. Second, a maintained parts database, because a device tag that resolves to a real part number is what makes the bill of materials, the terminal diagrams and the manufacturing data possible at all. Third, macros with value sets, which turn one drawn circuit into a family of drawings instead of thirty copied pages. Draw in EPLAN the way you drew in AutoCAD and you get AutoCAD results at EPLAN prices.

Structure identifiers, and the standard under them

IEC 81346 says an object can be designated from more than one aspect: what it does, where it is, and what it is. EPLAN implements that as structure identifiers, each with its own prefix.

A full designation reads ==WTP=A1+S1-K1:A1, water treatment plant, dosing function, cabinet S1, contactor K1, terminal A1. You rarely type all of it, because the page's own identifiers supply the leading parts and you type only -K1.

Set this in project properties before page one. The identifier structure decides how pages sort, how reports group, how the navigators filter, and how a device is found two years later by someone who has never seen the machine. Changing it mid-project is possible and unpleasant.

Page types are not cosmetic

The page type changes what the page may contain and how it reports.

• Multi-line schematic, the circuit. Symbols here are logical functions with connection points, and the connections between them become entries in the connection list.
• Single-line schematic, the overview. One line for three phases; useful for distribution, useless as a wiring instruction.
• Panel layout, a scaled arrangement of real parts on a mounting plate. You do not place schematic symbols here; you place the part, using data from the parts database.
• Overview, graphic, topology, for anything not electrically evaluated.
• Report pages, generated and regenerated. Never edit one by hand.

The schematic page tells EPLAN what is connected; the panel layout page tells it what is mounted where. Both point at the same device, which is how a wire can be given a real length later.

Devices versus symbols

This is the idea that separates a paying project from an expensive drawing.

A symbol is graphics plus a function definition, a coil, a normally open contact, a terminal. A device is a symbol that carries a device tag and a part number. Only the device exists downstream.

Place a contactor symbol, set the device tag to -K1, assign a part, and EPLAN now knows the coil voltage, contact allocation, terminal designations, DIN rail width and supplier. The coil on page 12 and its auxiliary contact on page 31 become one device, cross-referenced automatically, with a contact mirror on the coil showing which contacts are used and which are free. Without the part number it is a picture of a contactor with a name.

The parts database

The parts database is master data: manufacturer, part number, technical data, connection point designations, function templates, macro reference and, for Pro Panel, the 3D model. Manufacturer data comes from the EPLAN Data Portal; anything not there you create and maintain yourself.

An empty or half-maintained database costs you exactly the features you bought:

• no bill of materials worth issuing, because rows have no supplier or order number
• no terminal diagram with real terminal data, because the terminal part is unknown
• no correct panel layout, because the part has no dimensions
• no manufacturing data, no wire lengths, no labelling export, no drilling data

Somebody in the company has to own the parts database. If nobody does, EPLAN degrades into a drawing tool with a steep learning curve.

Macros, and the value set that makes one into many

The first three save drawing time. The value set changes the economics. Draw the starter circuit once, replace the specific values, motor tag, rating, contactor part, overload part, cable type, with placeholder objects, then define a value set per variant. Inserting the macro becomes: pick the variant, and the circuit arrives already tagged and already carrying its parts.

A worked example. A skid with twelve motors drawn as twelve copied pages: changing the overload range because one motor changed is twelve manual edits, twelve chances to miss one, and a BOM that disagrees with itself. As one window macro with twelve value sets it is one row in the value set table and a re-insert. The saving is not the first drawing; it is the fourth revision.

Macros also carry representation types and variants, so one macro can supply the multi-line circuit, the single-line version and the panel placement of the same starter.

The outputs that justify the licence

• Terminal diagrams and strip overviews, each strip with its terminals, jumpers, cable cores and both-side connections, generated from the schematic.
• Cable plans and cable overviews, every cable with type, core count, cores used and both endpoints.
• Bill of materials and device list, orderable, grouped by the structure identifiers you set at the start.
• Wire and terminal labelling, exported for a labelling machine, and for automated wire preparation where the shop has it.

All are regenerated on demand. If a report needs correcting by hand, the correction belongs upstream, in the schematic or the parts data.

What goes wrong

Copying pages instead of using macros. Fast on Monday, expensive at every revision, and it duplicates device tags so the first job is renumbering. It also guarantees the twelve starters diverge, because somebody will fix a mistake on nine of them.

Device tags that are only text. A symbol labelled with a text element reading -K1 looks right on the plot, does not exist in the device navigator, does not cross-reference, never appears in the device list and cannot be given a part. Check the navigators, not the page: if the device is not in the tree, it is not real.

A parts database nobody maintains. Parts invented on the fly, duplicates with different spellings, no connection point data. The BOM then needs a human to clean it before every order, which is the exact manual step the software was bought to remove. Take manufacturer data from the Data Portal and make local additions follow one naming rule.

What to learn next

Three things in order: terminals and cables properly, including multi-level terminals, jumpers and shield connections; PLC design, so I/O arrives by data exchange rather than typing; and Pro Panel, where the 2D layout becomes a 3D cabinet with routed wires and real lengths. If you are still choosing a package, read EPLAN vs AutoCAD Electrical vs SOLIDWORKS Electrical, and the control panel GA drawing covers the physical thinking no CAD package does for you.