@ggayDiamond I've fixed the length of fast_cs names to 40 but we can still get PVNames that exceed 60, that is because the prefix and the terminal tree e.g. IOC:ETH1:ROI1:MOD1 gets added on.
When writing the tutorials I found I was getting the error with the prefix TUTORIAL, but shortening to IOC fixed it.
So we need to do something later at PV name generation time, in addition to limiting the fastcs_name length.