This was not necessary before we set up the ring network for the PLCs.
Did this change happen to coincide with updating to 8.3.3 from an earlier 8.3 version?
There's a nasty bug in 8.3.3 where the driver will often not detect an error when making symbolic read/write calls. This prevents the driver from reconnecting when it should.
This is not an issue in 8.3.2, it is fixed in the 8.3.5 nightly, and will be fixed in 8.3.4 when it is released (but is not fixed in 8.3.4 RC1).
My guess is that you're hitting this issue. But, if you still see the issue on 8.3.2 or 8.3.5, let me know.