QMH logging multiple loops

[Patrem1]

Hi,

I’m restructuring an existing project someone else did that had approx. 10 loops in parallel with no framework. I chose to use the QMH framework and I now have the basic functions of each hardware (inputs/outputs) loops working.

I now need to add a data logging loop. The old program just read all the controls on the front panels as local variables and logged data with that. I know how to write data to file but I’m not sure which method to use to get the data from multiple loops and send it to the data logging loop.

Other infos :

-Data is acquired at around 5Hz and will be logged at around 1Hz

-The timing between the data coming from each loop is not critical. Anyway it is already not in sync coming from a mix of DAQ devices and serial communication. But the solution should at least write the most recent data from each loop.

-I will not change the framework again for now. Yes, I know after 10 years of experience you know of a better framework for this.

My 2 ideas for now :

1. When instructed, all the required loops send a message to the ‘logging loop’ with the data as ‘message data’. The logging loop write the data once it received data from each required loop.
2. Use notifiers. Each loop would write their data in a notifier and the logging loop would write the lastest data of each loop by reading all notifiers.

Thank you,

[JÞB]

That begs the question "Do you need to log every value or just snapshots of the Acquisitions?"  Would you rather log pt by pt statistical values? 

Those answers drive how you need to send data to the logging loop.