Chains

What is a chain?

A chain connects several templates into one overall system so their fault knowledge can be used together during troubleshooting.

The core principle is additive: instead of maintaining one huge heatmap for the entire machine, you build the overall knowledge from parts. Each template is a part (a component or area) and brings its own knowledge – its own symptoms, its own causes and its own (partial) heatmap. In the chain these parts are appended, and on top you define the cross-area connections between them.

In short: A template holds the knowledge for one component/area. A chain combines several templates additively. The chain itself is the shell of the overall machine – it is not a component template of its own.

When do I need a chain – and when is a single heatmap enough?

Use a chain when …

• your machine consists of several larger areas,

• these areas have their own fault knowledge,

• a cause in one area can trigger a symptom in another area,

• you want to reuse the same template across several machines,

• a single heatmap would become too large/cluttered.

Use a single heatmap when … everything happens within one clearly delimited area.

Rule of thumb: Everything in one area → heatmap. Several areas interacting → chain.

Key terms: Template, Chain and Machine

Template – a knowledge template for a component/area (symptoms, causes, likelihoods, routines).

Chain – connects several templates additively into one overall system.

Machine – a concrete machine that works with knowledge. A Machine can also be created from a chain. When putting together components in a chain you do not need a shell to connect them. The machine will be the shell.

How to create and use a chain

1. Create a new chain

Open "Chains" on the left and click "New chain" in the top right. Give it a name and choose or create a type. Optionally add a cover image. Click "Save" to create the chain.

2. Use the chain canvas (add templates as nodes)

Open the chain and switch to the "Chain" tab (canvas). Use the template/add panel to search for a template and drag it onto the canvas via drag & drop. Each template becomes a node (= one area of the machine). Use the zoom/fit-view buttons at the bottom to arrange the nodes.

When you use one template several times in a chain (e.g. the same conveyor belt is built into a production line multiple times), you can name the instances individually, so the operator knows where to look when a symptom of that template is queried during troubleshooting.

3. Create a connection and maintain the partial heatmap

Drag from a connection handle of one node to another node – the connection is created. The number on the connection shows how many cross-area cause→symptom links are already defined (0 at first).

A click on the number/connection opens the connection editor: at the top you pick the cause template and the symptom template; the ↔ button flips the reading direction (which area provides the cause, which the symptom). Below you see the partial heatmap for exactly this area combination and enter the values. These are the same values that appear in the chain heatmap (step 4) as the "cross block" of these two templates – you can maintain them in either place. Use "Open heatmap" to jump into the filtered chain heatmap.

4. Work in the chain heatmap

Open "Heatmap" in the menu. The chain heatmap shows the knowledge of all templates in one single table: every row is a cause, every column is a symptom, grouped by template (e.g. "… Hydraulics (subsystem)", "… Mechanics – Frame & Ram", "… Lubrication System").

Because of this grouping, the table falls into blocks:

• Blocks on the diagonal – cause and symptom come from the same template. These values come from that template's own heatmap. You can maintain them here too – the changes are also applied to the original heatmap.

• All other blocks ("cross blocks") – the cause comes from one template, the symptom from another one. They are empty at first, and this is where the chaining happens. These are the same values you already saw in the connection editor in step 3.

How to link a cause and a symptom from two different templates:

1. Find the row of the cause, e.g. "Clogged lubrication line" (Lubrication System).

2. Find the column of the symptom in the other template, e.g. "Juddering ram movement" (Mechanics).

3. Click the cell where that row and that column meet and choose a frequency: Always / Often / Rarely / Never.

Read every cell as one sentence: "If [cause] is present, [symptom] occurs [frequency]."

Use the toolbar at the bottom to change sorting and view and to open the heatmap in full screen.

Tip: Without values in the cross blocks the areas stay isolated. For real chaining, deliberately enter likelihoods there.

Three examples from practice

Example 1 – Subsystems: Hydraulic Press

A hydraulic press is the example used above as well. It consists of several subsystems that are maintained as their own templates and connected in a chain: Hydraulics, Control, Mechanics (Frame & Ram) and Lubrication System. The chain is the press itself (shell), the subsystems are the parts.

Cross-area effects, e.g.:

• Lubrication System → Mechanics: "Clogged lubrication line" → "juddering/jerky ram movement"

• Mechanics → Control: "Damaged guide rail" → "machine stops unexpectedly"

• Hydraulics → Control: "Worn pump" → "machine stops"

Example 2 – Production line: Woodworking

A production line consists of stations in series: Debarking → Lathe → Milling (Variants) → Assembly/Final Inspection. A fault at an early station often only becomes visible at a later one (faults travel downstream).

Example 3 – Equipment/options: Combine Harvester

A combine harvester consists of a base machine plus various equipment options (attachments/add-ons) that are added depending on the configuration. Each option is its own template and is connected to the machine in the "Combine Harvester" chain. This lets you model an individually equipped machine without maintaining a separate huge heatmap for every combination – and you can reuse individual options (e.g. the moisture sensor) in other machines too.

Equipment options as templates, e.g.:

• Automatic Header Height Control

• Yield Mapping System

• Moisture Sensor

• Grain Tank Scale

• Touchscreen Control Terminal

Cross-area effects, e.g.:

• Moisture Sensor → Control Terminal: "Sensor returns a wrong reading" → "wrong moisture value on the display"

• Yield Mapping System → Control Terminal: "Sensor/camera disturbed" → "gaps in the yield map"

Troubleshooting / Test run in the chain

Use "Start test run" to test troubleshooting across the entire chain. The diagnosis uses the combined knowledge of all areas including the cross-area connections.

Limitations and common pitfalls

• Don't forget the cross values: Without entries in the cross blocks the areas stay unconnected. You can still create and use a machine – but troubleshooting stays disjointed and is hardly usable without filtering.

• Duplicating a chain / chain within a chain: currently limited; model complex systems via clear subsystem templates instead.

• Several production lines in one chain: only useful if the lines really work the same way – otherwise likelihoods get mixed up.

• Unlinked causes/symptoms are not actively used in the chain troubleshooting.

• Variants of chains: The variants feature is still under development. Using the filter on the chain heatmap you can already create variants of a chain and check them in a filtered test run. They are not usable for the operator yet.

FAQ