What is the string plan for?
The string plan shows on the roof which panel belongs to which string and which MPPT and inverter each string is connected to. Eturnity generates it as a PDF from your string design – with string colours, string names and a legend that lists the number of panels, the open-circuit voltage and the power for each string. Previously, a plan like this was created by hand in a CAD program or with copied tables, and every change to the design meant recalculating and redrawing.
The string plan is usually created by technical planners or project managers when a project moves into implementation after the order has been signed. It is intended for:
the installation team – which panel goes on which string
the person who commissions the system – they compare the measured voltages with the plan
authorities in the approval process
your customers as part of the project documentation
String plan, roof plan or single line diagram?
String plan – which panel belongs to which string and MPPT
Roof plan – the mechanical position of the panels with dimensions and obstacles, as the basis for mounting
Single line diagram – the electrical connection of the main components with the protective devices, without reference to their position on the roof
The string plan and the roof plan are created on the same canvas but are separate documents: what you design in one does not appear in the other.
Core principle: Planning is done in the 3D Panel layout and the string design; the string plan only adds annotations. So always change the wiring on the Inverter page – the plan picks up the change with a click on Update.
License Note: If the string plan opens blurred with an upgrade window, it is not included in your current license. It is activated separately from the roof plan. In the upgrade window, click Start free trial to begin a trial, as long as your company has not used it yet. Click Upgrade now to request an upgrade; our team will then get in touch with you. To learn more, contact support@eturnity.com.
Prerequisites
The Photovoltaics technology is active in the variant.
The variant has a roof drawn in the 3D Panel layout.
The string design is complete. Without strings, the plan shows no wiring.
You are working in Chrome, Edge or Firefox – the string plan does not open in Safari.
How to find the page: Open the project > Planning group in the left-hand side menu > String plan. Each variant has its own string plan.
Your first string plan
When you open it for the first time, the Select a roof window appears. Leave Entire project selected – this view is sufficient for most string plans – and click Add roof.
The Edit roof window opens. Click Save at the bottom. You return to the page, and the roof is placed on it – with the strings in their colours.
Click the roof on the page. The Roof element settings sidebar appears on the left. Under Layer visibility, switch on String labels; they are off by default.
Drag the roof to the position you want on the page and resize it using the corner handles. The aspect ratio is preserved.
Click Generate PDF in the tab bar at the top. The preview opens with the Export file sidebar.
Enter a File name and click Save document. The PDF is then stored in the project's File manager, assigned to the variant.
Everything else is optional and is described under Customise the plan.
How the canvas works
Everything on the page is an element: the roof, the legend, the title block, texts, frames and arrows. You can move any element with the mouse; the roof can also be enlarged or reduced at its corners. This lets you arrange the page the way you need it – for example, an overall view next to individual roofs, plus the legend and title block.
If you click the roof, the legend or an arrow, its settings appear on the left-hand edge. You edit texts and the title block directly on the page. To open the settings for the whole page, use Settings in the toolbar; they appear on the right-hand edge. Each page of the plan is a separate tab.
To save, use the floppy disk icon. If you leave the string plan for another part of Eturnity, Eturnity saves automatically beforehand.
Customise the plan
Organised by where you find the setting.
In the "Edit roof" window
You reopen it by double-clicking the roof. Apply your changes with Save.
Optimisers: Select the Optimiser tool, mark the panels that have an optimiser and, in the Panel settings sidebar, switch on Add optimiser. The panels then show an icon, and the legend counts them. You set this marking yourself in the string plan; optimisers from the string design appear in the legend with their name and quantity.
Cable routes and notes: Use Polyline, Polygon and Circle to draw, for example, where the cables run from the roof to the inverter. Under Label in legend, give the element a name for the legend.
On the roof placed on the page
Click the roof; Roof element settings appears on the left.
Layer visibility: what the roof shows – for example, show the String labels or hide the Obstacles so that only the wiring remains in view.
Scale: if the plan is to be printed to scale. The title block takes the scale of the first roof element that appears in the legend – unless you enter your own value there.
Show roof elements in legend: switch off for small overviews (see Versions for different recipients).
On the legend
Click the legend; the Legend settings appear on the left. There, under Sections visibility, you can hide entire sections – for example the roofs, if the plan should only show the wiring – and set the No. of columns. Add your own note with Add field: the button appears at the bottom of the legend as soon as you hover over the selected legend. There is one such field per legend. The legend can be moved freely on the page.
Page and title block
Settings in the toolbar opens the Page settings on the right-hand edge, with Format (A4 to A1), Orientation and Font size.
Click the title block to edit the document type, scale and version directly. The page name and page format come from the page; the other details come from the project, customer and company data.
Read the plan
Each string is named according to the pattern Inverter.MPPT.String: 1.1.2 is string 2 on MPPT 1 of inverter 1. Administrators can change the pattern for the whole company, for example to 1.A.1 – under Settings > Inverter design, String label naming tab.
In the Strings section, the legend lists all strings for each inverter with their MPPT, number of panels, open-circuit voltage (Uoc [V]) and power (P [kWp]).
Open-circuit voltage: Whoever commissions the system measures the open-circuit voltage of each string and compares it with the plan. Eturnity calculates the value from the panel datasheet values; depending on the panel temperature, the measured value will differ from it.
All strings of an inverter: If a page shows only one roof, the legend still lists all strings of the inverters concerned – including those on other roofs. This way, the installation team never sees only part of the string assignment.
Language: The legend and title block appear in the project's Correspondence language, because the plan goes to customers and authorities. You can change it in the Project settings.
Versions for different recipients
The installation team and the authorities often don't need the same information. Duplicate a finished page via the three-dot menu on its tab and, on the copy, hide what the recipient doesn't need. When generating the PDF, you then choose the appropriate pages and a descriptive file name for each recipient, such as "String plan – authority".
For large buildings, an overview page with the entire project plus one page per roof has proven effective. For a small overview, switch off Show roof elements in legend; otherwise, the legend also counts the roofs, panels and strings of the entire project.
Update after design changes
After a change to the panel layout or the strings, hover over each roof element: an outdated one then shows the Outdated badge and the Update button. One click applies the new data; your layers and drawings are retained. If a changed string runs across several roofs, no badge appears on an element showing a single roof – in that case, open it by double-clicking and click Save.
Good to know
Checking local requirements is up to you. Which colours, views and details a plan must contain varies by country and often by municipality. Eturnity therefore gives you freely configurable tools instead of rigid templates, but does not guarantee that a plan meets any particular requirement.
No combined PDF: The roof plan, string plan and single line diagram are saved as separate PDFs. You put together a package for each recipient outside Eturnity.
No version history: Keep earlier versions as PDFs in the file manager. The version field in the title block helps you tell them apart.