# Monitors Strand¶

The configuration_values_schema, input_values_schema and output_values_schema strands are values-based, meaning the data that matches these strands is in JSON form.

Each of these strands is a json schema which describes that data.

There are two kinds of monitoring data required from a digital twin.

Monitor data (output)

Values for health and progress monitoring of the twin, for example percentage progress, iteration number and status - perhaps even residuals graphs for a converging calculation. Broadly speaking, this should be user-facing information.

This kind of monitoring data can be in a suitable form for display on a dashboard

Log data (output)

Logged statements, typically in iostream form, produced by the twin (e.g. via python’s logging module) must be capturable as an output for debugging and monitoring purposes. Broadly speaking, this should be developer-facing information.

Let’s look at basic examples for twines containing each of these strands:

Monitor data (output)

Log data (output)