Yeah, that's an endless story...

But it seems, that the connecting of shield at only one end is from the old days. Seems, that connecting it at both ends to chassis ground (protection earth) tends to prevail.

By the way, due to the fact that RS485 routing uses symmterical signaling the shield is nearly free of signal return currents. It behaves totally different compared to a coax cable, where the cable shield carries all the signal return current and must always be connected to signal ground.

So, for the RS485 there's no need to connect the cable shield to signal ground for all the signal frequencies. This means, that the shield can be connected to chassis ground while the signal ground is floating (at both ends, if you want). Connecting the signal ground at both ends via a cap of 10...100nF would allow the shield being connected for the highest harmonics of signals to allow them to use the shield as signal return to handle the imperfections of cable, means finite symmetry.

So, the cable shield can be hard grounded (connected to safety ground, chassis) and the signal ground can be soft grounded. As it can be seen with PROFIBUS applications.

Kai