Apart from what RicardoTM mentioned, SysInfo became a regular measure some time ago, so it's not a plugin anymore. Normally, if the SysInfo measure precedes the Ping one in the code and its logical workflow, you should simply need to use the former as the value of the DestAddress option from the latter, e.g. DestAddress=[YourSysInfoMeasure], and have DynamicVariables=1 on the Ping measure, like RicardoTM suggested as well. Using a variable to hold the value of the SysInfo measure shouldn't necessarily be needed. Also, neither the SysInfo nor the Ping measure have an "AfterFinish" option, only the Ping measure has a FinishAction on it and shouldn't be needed given that you trigger the Plugin measure from the SysInfo one and not the other way around.
Statistics: Posted by Yincognito — 42 minutes ago