Added a short delay to ensure timely PDOs

[preston-rogers]

It was found that some devices, specifically Platinum drives, would not transition into operational state. From debugging, research, and headaches, it was found that the issue was due to non-timely sending of PDOs. When PDOs are not sent at a timely rate, the slave will not transition to Operational mode.

This information is presented here:

https://github.com/OpenEtherCATsociety/SOEM/issues/224

"Mostly a 1ms cycle time will work. When the slave sees enough LRW packets at a constant interval it will lock to that and release to Operational."