The guides

Six short guides, written for someone who has just run the examples. They are not the product reference — they are the why behind what you have already seen working.

	Read it when
01_The_Element_Tree.md	You want to talk to a real device. <con> / <dev> / <bi> / <io>, addresses, sta, how a value gets from the wire into the tree.
02_Timers_and_Events.md	You want something to happen on its own. Threads, evt_*, why a write runs a chain of functions.
03_Scripting.md	You want to write the logic. Where script lives, how XML calls it, the six places the language is not JavaScript, and web pages written in script (.ayp).
04_Licensing.md	You want to know what is free, what is not, and why the replication example runs anyway.
05_Connections_and_Protocols.md	You want to reach something outside the engine. Transports and protocols, who dials and who asks, one port for several services, polled against subscribed, and what to do about a protocol AyMON does not speak.
06_Access_and_Safety.md	You are about to let something in. The three gates — con_acl, the login, xdb_acl — TLS, and what the examples deliberately leave open.

Suggested order

Run the example, then read the guide. Not the other way round — every guide assumes you have seen the thing work.

PRJEDU_101      →  02_Timers_and_Events   →  03_Scripting
PRJEDU_modbus   →  01_The_Element_Tree    →  05_Connections_and_Protocols
PRJEDU_sqlite   →  03_Scripting  (the SQL section)
PRJEDU_odbc     →  03_Scripting
PRJEDU_mqtt     →  05_Connections_and_Protocols
PRJEDU_snmp     →  05_Connections_and_Protocols
PRJEDU_net      →  05_Connections_and_Protocols  →  04_Licensing
PRJEDU_opcua    →  05_Connections_and_Protocols  →  06_Access_and_Safety
PRJEDU_web      →  05_Connections_and_Protocols  →  06_Access_and_Safety
PRJEDU_pages    →  03_Scripting          →  06_Access_and_Safety
PRJEDU_telnet   →  06_Access_and_Safety
PRJEDU_hardening → 06_Access_and_Safety
PRJEDU_mcp      →  06_Access_and_Safety   →  04_Licensing
PRJEDU_rep      →  04_Licensing
PRJEDU_cluster  →  04_Licensing          →  03_Scripting
PRJEDU_gauge    →  03_Scripting
PRJEDU_pycall   →  03_Scripting
PRJEDU_vision   →  03_Scripting          →  05_Connections_and_Protocols
PRJEDU_pid      →  02_Timers_and_Events  →  03_Scripting
PRJEDU_plc      →  01_The_Element_Tree   →  05_Connections_and_Protocols
PRJEDU_oee      →  03_Scripting          →  05_Connections_and_Protocols
PRJEDU_robotarm →  05_Connections_and_Protocols  →  03_Scripting
PRJEDU_robot_mcp → 06_Access_and_Safety  →  04_Licensing
PRJPER_tello    →  05_Connections_and_Protocols  →  06_Access_and_Safety
PRJPER_adsb     →  01_The_Element_Tree   →  05_Connections_and_Protocols
PRJPER_phone    →  01_The_Element_Tree   →  06_Access_and_Safety

PRJEDU_101 is the one to run first. It has no hardware, no database and no second engine: a thread, a timer, a value, a calculated value and an alarm — which is most of AyMON in forty lines of XML.

If you are here because of one particular job, start at the example that does it: a device to poll (PRJEDU_modbus, PRJEDU_snmp), a machine with an OPC UA server (PRJEDU_opcua), values to publish or subscribe (PRJEDU_mqtt), a page to put them on (PRJEDU_web), history to keep (PRJEDU_sqlite, PRJEDU_odbc), a second engine to feed (PRJEDU_rep), a second engine to take over (PRJEDU_cluster), a way in while it runs (PRJEDU_telnet), a plant's access to harden (PRJEDU_hardening), an AI assistant to let in (PRJEDU_mcp), Python and image processing next to the engine (PRJEDU_gauge), Python called from the XML and from script (PRJEDU_pycall), a camera to inspect a line with (PRJEDU_vision), mail to send and files to upload (PRJEDU_net), a control loop to tune (PRJEDU_pid), a machine to program (PRJEDU_plc), a line's OEE to account for (PRJEDU_oee), a robot arm to run in a cell (PRJEDU_robotarm) and an AI assistant to let run it (PRJEDU_robot_mcp), a drone to fly (PRJPER_tello), the aircraft overhead to track (PRJPER_adsb), a phone's sensors to watch (PRJPER_phone).

One page of vocabulary

Everything in AyMON is an element with attributes, arranged in a tree that looks like XML because it is:

<var id="LEVEL" val="72.4" val_typ="0x1308" sta="0x0303" val_unt="%"/>

• id addresses it. id('LEVEL') finds it anywhere in the document without walking the tree.
• val is a value; so is sta, so is evt, so is pro. There is nothing special about val — an attribute is an attribute.
• val_typ says what kind of value it is. Types are real: 0x0308 is a double, 0x0104 an unsigned 32-bit integer, 0x0401 a string. A value keeps its type when it is written to a database, published over MQTT or replicated to another engine.
• sta is the element's state — one 16-bit word that carries "is it running", "is it in alarm" and "what has the operator asked for".
• val_fnc is a chain of functions that runs when val is written. That is the whole event model: a write runs a chain, and the chain may write again.
• pro is the same idea on the wire side: what the device said, before anyone decided what it means. pro_fnc="[VAL.put]" is what carries it across.

A document is a file of elements with a name like HIS/S00. One engine runs several documents; they can address each other (doc('PRC/P01')/id('LEVEL')/@val) and a document is also the unit that gets replicated, logged and licensed.

Where the full reference is

These guides are deliberately small. The complete field notes — SNMP, OPC UA, MQTT, cluster and replication, access control, authentication, the plug-in SDK, the Python module, telnet, raw protocols, load metrics, mail (SMTP), file transfer (FTP, SFTP) and file functions, camera capture and image functions, blob, decimal and time values — come with the licensed product. If you are doing something the examples do not cover, that is where to look.