From 468ffe901fa3fb07fdc33b70173a82149adbf0f0 Mon Sep 17 00:00:00 2001
From: "Ritesh.K" <riteshkarki6@gmail.com>
Date: Mon, 16 Mar 2026 00:29:23 +0100
Subject: [PATCH] Add documentation for FMU node type

Signed-off-by: Ritesh.K <riteshkarki6@gmail.com>
---
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+---
+hide_table_of_contents: true
+---
+
+# Functional Mockup Unit (FMU) 
+
+The `fmu` node-type can be used to control and communicate with an existing fmu model and step through its simulation through VILLASnode. 
+
+## Prerequisites 
+
+This node-type depends on the availability of the FMI3.0 specified C API ([fmi-library](https://github.com/modelon-community/fmi-library.git)). Please note that this node works only with FMU models implemented with FMI 3.0. 
+
+## Implementation 
+
+The source code is available here: 
+https://github.com/VILLASframework/node/blob/node-fmu/lib/nodes/fmu.cpp
+
+The implementation consists of interface abilities with Co-Simulation type of simulators, specificaly [`Basic Co-Simulation`](https://fmi-standard.org/docs/3.0.2/#_basic_co_simulation) and [`Early Return`](https://fmi-standard.org/docs/3.0.2/#_early_return).
+
+## Configuration {#config}
+
+Every `fmu` node can be considered as a gateway for a single model. Multiple models can be interconnected by configuring them as individual nodes and connected through `paths`.
+
+import ApiSchema from '@theme/ApiSchema';
+
+<ApiSchema id="node" example pointer="#/components/schemas/fmu" />
+
+## Example 
+
+``` url="external/node/etc/examples/nodes/fmu.conf"  title="node/etc/examples/nodes/fmu.conf"
+odes = {
+    file_output = {
+        type = "file"
+        # format = "csv"
+        uri = "/workspaces/node/fmu_temp/output.dat"
+        out = {
+
+        }
+    },
+
+    signal_node = {
+        type = "signal.v2"
+        rate = 100.0
+        realtime = true
+
+        limit = 100
+
+        in = {
+            signals = (
+                { name = "sine1",   signal = "sine",   amplitude = 1, frequency = 100   },
+                # { name = "in2",   signal = "constant", amplitude = 1  },
+            )
+        }
+    },
+    fmu_node = {
+        type = "fmu"
+        # Path to fmu file
+        fmu_path = "/workspaces/node/fmu_temp/asine.fmu"
+        fmu_unpack_path = "/workspaces/node/fmu_temp/fmu_asine"
+        fmu_writefirst = true
+        stopTime = 10.0
+        startTime = 0.0
+        stepSize = 0.2
+
+        in = {
+            signals = (
+                {name = "In1", type = "float"}
+            )
+        }
+
+        out = {
+            signals = (
+                {name = "Out1", type = "float"},
+            )
+        }
+    }
+}
+
+paths = (
+    {
+        in = "signal_node",
+        out = "fmu_node"
+    },
+    {
+        in = "fmu_node",
+        out = "file_output"
+    },
+)
+```
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