Lua API Extensions Reference

Overview

Lua has a standard library which defines its core functionality. To work with Cognio, a script also needs access to its Control Panel Group, the device it runs on, and the network, so Symetrix has created a set of custom Lua API (Application Programming Interface) extensions.

The following pages describe the Symetrix extensions to Lua that you can use in Control Panel Group scripts, including the scripts in 3rd party Lua control drivers. They are not available in the Scripted modules in the Signal Flow Toolkit.

• Controls
• Device
• HttpClient
• JSON
• NamedControl
• SSH
• System
• TcpSocket
• Timer
• UdpSocket

Conventions

In the code examples, you will commonly see the following to the right of lines of code:

print("Ben")                  >> Ben
ChangeLabel("Ben")            -- The label was changed to "Ben"

The first line prints to the Lua Script Debug Output File. The output of this print statement is indicated with the ">>".

The second line does something in the code but has no output to the Lua Script Debug Output File. As such, the result of the line is described with the comment indicator "--".

More Lua Information

Cognio scripts use Lua 5.4. For more information about Lua, see the Lua 5.4 Reference Manual.