How do I gateway "System Name" in script?

[frank.carney]

I want the System Name in script so I can build up dynamic pens for my Easy Chart. For some reason the tag path in the historian requires this:

[PGriffith]

You can read the [System]SystemName tag:
https://docs.inductiveautomation.com/display/DOC81/System+Tags#SystemTags-GatewaySystemTags