I’ve been working with DCS systems for over 20 years. IMHO it’s a great move. There is a lot of work around at the moment, and you should find it easy to break into it. Salaried roles are typically c.30K Junior, c.45K senior, depending on experience. Contractor rates are typically c.30-50p/h, DOE and the industry sector.
The most typical way to start is to work for a small integrator, and basically eat s*** for 2-3 years, then go contracting. This is typically not a comfortable time (you will be thrown in at the deep end), but it gets you up the learning curve. You may me able to jump straight into a contract role, but it will probably be boring, and difficult to get good experience. A good agent is a massive help.
Where are you located? Drop me a mail of you want to discuss anything away from the forum.