Handle switch debouncing functionality

1

Dear IPMC team,

I wanted to ask if it would be possible to add a feature to IPMC software or firmware, that adds some debouncing functionality to the handle switch.

We recently encountered an unexpected shutdown of one of our Ph1Topo modules in ATLAS. The shelf manager logged the cause of the shutdown as an opening of the handle switch. This happened at 3 AM, so nobody was in the cavern. The board also powered on again instantly (handle switch closed). Our theory is that some vibration toggled the handle switch for a short period (O(ms)). Similar behavior was already observed with modules from other groups.

A debouncing functionality in the IPMC could help mitigate the effect of such a non-optimal handle switch mechanical behavior. If a user could define a time in milliseconds in the XML for which the handle switch must be consistently open/closed before a transition is triggered, the issue would be mitigated.

Thank you very much and cheers,
Emanuel

2

Hello Emanuel,

the IPMC software already supports handle switch debouncing, it just needs to be enabled in the XML configuration, see the example below:

<HandleSwitch active="LOW" inactive="HIGH" debouncing="10"/>

The parameter after the “debouncing” keyword is the debouncing delay in ms. Unfortunately this feature was not at all documented, so it was generally not used. We will update the documentation accordingly.

Let me know if this helps with your problem.

cheers,

Stefan

3

Dear Stefan,

thank you very much for the swift reply. This will help us immensely.

Cheers,
Emanuel