Overview

QSC is a professional audio/video system solutions provider. Its software-based platform is called Q-SYS. Q-SYS is designed to allow third-party systems to control and/or monitor various aspects of the system by writing your own code using different communication protocols.

The Q-SYS software supports following ways of external control:

• Named Controls – Controls that have been placed at Named Control pane. The names of the controls must be different. [This is part of the Q-SYS control level.]
• Component Control – Control all controls within any component by customizing the name of component to make it unique. [This is part of the Q-SYS component level.]
• Mixer Control – Specialized control of mixers using mixer concepts. [This is part of the Q-SYS component level.]

Basically, there are two different protocols provided by QSC to access the three above mentioned external controls for Q-SYS. They are called "Q-SYS External Control Protocol" and "Q-SYS Remote Control" (QRC in the following).

• Q-SYS External Control Protocol:
• Q-SYS External Control Protocol is based on ASCII and using TCP/IP connection on port 1702 and it requires the use of Named Controls for any control which should be externally controlled. This means it only supports Q-SYS control level functions.
• QRC:
• QRC is the latest and most advanced protocol provided by QSC to allow an external control system (e.g. TwinCAT) to control various functions within Q-SYS. The QRC protocol is based on JSON-RPC version 2.0 and is using TCP/IP connection on port 1710. QRC supports the use of all three above mentioned controls: Named Controls, Component Control and Mixer Control. Based on that it allows the external access at control level and component level.

The precondition of external access at control level, is that every control in Q-SYS you want to be controlled, must be dragged into the Named Controls pane and the name of it must be unique.

In this document, how QRC can be used with Beckhoff controllers (TwinCAT software) will be explained. An example code called Tc3_Qrc library will also be provided in attachment.

The Tc3_Qrc library enables the implementation of one or more QRC external clients in the TwinCAT PLC. With its help, a Q-SYS Core can be controlled directly from a TwinCAT program.

QRC controls can be mapped to any data types in TwinCAT. This allows a large range of communication possibilities for the system integrator.

The QRC specification can be found here.

The QRC specification and its features are designed and developed by QSC, specification may be changed in the future.

QSC and Q-SYS are trademarks of QSC, LLC. The QRC specification and associated documentation is copyright QSC, LLC.

Further information about the activities of Beckhoff in the market stage and show can be found on our website at: PC-based Control for Stage and Show Technology

System Requirement

Test network

Before launching a project that involves the use of any network protocol, it is crucial to ensure that the network being used is functioning correctly. We recommend starting with a simple test where the Beckhoff device has a direct connection to the device it should communicate with. With no Firewalls or similar active.