It rather depends on the job description but my take from where I have seen these roles in the past

1) Very little. One is an advisory job about an organisation developing its people to add value. The other is an administrative job about scheduling people against work patterns

2) No it is generally an Operations job that reports into a separate line.

3) Very little (in my opinion) as its really an entirely different skill set

Keith has said most of it. I would simply add that in a company with various types of shift work that require complex rostering, the HR person would need to understand the basics principles. Without this understanding they will be badly placed to have meaningful discussions with line managers, staff or understand the implications in pay terms of how a shift change or roster change will impact the person's payments....... or the company's costs. They will probably also need to be able to advise planners/rosterers on issues surrounding the WTD

In reply to Keith:

Thank you Keith. Your illustration has helped me to understand more about the 2 roles.

In reply to Ray:

Thank you Ray for adding info on top of Keith. It's certainly a helpful post.