Use this document as a guide for IPv4 organization. As an integrator, it is important to know which IP addresses are going to which devices. This chart suggests an easy way to keep track of them, having a standard structure for all projects to follow. The chart lists what type of device it is, and it gives a range of numbers for the last octet of the IP address of each device.
Full PDF - Clare Controls IP Mapping (DOC ID 824)