Not sure if this is your first attempt at programing a PLC or if this is your first attempt at building a control circuit but here are a few points
Idec is a low end PLC with lots of limitations. So you need to check your requirements very carefully.
Do you need Com's to another system
How Many Inputs and Outputs do you need
What kind of Inputs and Outputs do you need Analog or Discreet or both
How fast must you process
Do you need expandablity
All of these questions and a more that I have not mentioned decide which PLC you can use. Since we are not building your machine we can not give you any more than you supply.
FYI... In PLC's you have all types of data formats, Bits, Bytes, Double Intergers, Words, Double Words, Floats, Reals, Time, BCD....and the list goes one. Which ones your PLC can use is in your manual. Look under data types to find this info.