Flexs Q5C Scripting Reference

The Flexs Q5C is configured through its on-board web interface using an editable script. Scripts are interpreted with mJS, a restricted JavaScript engine for embedded systems — most everyday JavaScript syntax works, but there is no dynamic eval, no closures over freed objects, and the standard library is the set of device functions documented here.

Script lifecycle

A script starts automatically at boot and restarts approximately 1 second after it exits or crashes. Continuous loops must be bound to the run() function so the device can stop the script during configuration updates:

while(run()){
  // your monitoring logic
  waitMS(100);
}

Warning — deployment safety. Bad scripts can cause unexpected behavior including device restarts, lockups and relay state changes. Always test thoroughly in a non-critical environment before deploying. Give the script enough runtime to confirm proper operation before committing configuration changes, so the device can boot back into a known-good configuration if a critical error occurs.

The 5-second shutdown rule

Scripts must not block for more than 5 seconds after run() returns false. If your script does not exit within that window it will not be updated during configuration changes, a device restart will be required, and unexpected behavior may result because objects referenced by the script can become undefined after the configuration changes.

IO synchronisation

The IO variables are synced with local variables whenever run() executes. If you need to update IO points mid-loop, call syncIO() manually.