Glossary

Term	Meaning
API key	A key that lets a script or device read or write data without a password. Each account has a read only key and a read and write key. See My Account.
App	A ready-made dashboard for one application, such as solar or a heat pump. See Apps.
Cumulative kWh feed	A feed of total energy that only rises, like a meter reading. Daily kWh is the difference between the values at the start and end of each day. See Daily kWh.
Dashboard	A page you build from widgets and charts. See Dashboards.
Device	A group of inputs from one node, set up from a template. See Devices.
Device key	A key that lets one device post data to its own node only. See Devices.
emonHub	Software on the emonPi and emonBase that reads data from the hardware and passes it to Emoncms.
emonSD	The software image for the emonPi and emonBase.
Engine	The storage format of a feed: fixed interval, variable interval or virtual. See Feeds.
Feed	A stored time series of values. See Feeds.
Input	The latest value received for one node and key. See Inputs.
Input processing	A list of steps that runs on each new input value, such as scaling it or logging it to a feed. See Inputs.
Interval	The time between values in a fixed interval feed, for example 10 seconds.
Key	The name of one value from a node, for example P1 or temperature.
MQTT	A messaging protocol used to pass data between emonHub, Emoncms and other software. See MQTT.
Node	The name of a device or source that sends data, for example emontx4. Inputs are grouped by node.
Post process	Processing applied to recorded feed data. See Post process.
Public feed	A feed anyone can read without logging in.
Schedule	A set of time windows used by input processing, for example for tariff periods. See Schedules.
Tag	A label that groups feeds on the Feeds page. Often the node name.
Virtual feed	A feed that stores nothing and calculates values from other feeds when read. See Virtual feeds.