What is difference between CampactLogix and ControlLogix PLC ?

Difference Between CampactLogic and ControlLogic.... 1.  I/O - The analog I/O on the control logix allows you to scale directly with the card setup.  This can save some time in programming; however, with the use of remote I/O this advantage goes away.The scaling instructions in the logix  are simple and quick so your really do not have much of an advantage here.  I suspect there are also advantages in the amount of I/O points available to the control logix, however, I have generally run into problems with communications or memory use before having a problem with the amount of I/O that can be used. 2.  Memory - The controlLogix processors can give you significantly more memory to work with.  This makes them much better suited to bigger systems. 3. Communications - This is the area that the control logix has the biggest advantage.  There are many ways in which it out performs the compact logix  here.  First, and most obvious, are the communication cards available.  Except for the L4x, The communication are built into the compact logix.  The L4x series has a separate Ethernet I/P card which can be useful, but it still has few communication options available.  The only communication module available to all of the compact series is device net (yuck).  You can get a compact with Control Net, but then you lose your Ethernet I/P port.  So with the compact it is one or the other.  The control logix has a wide array of communications modules available (Ethernet I/P, Control Net, DeviceNet, DH+, Profibus, etc).  There are Rockwell cards and third party cards available.  With the gateway capabilities of the logix platform, this makes it very powerful.  Finally the control logix has the ability to communicate with more end devices on its Ethernet I/P modules.  One gotcha with Ethernet I/P is the limitations of TCP connections and CIP connections.  Every time you drop I/O or interface with a Panelview  HMI you use up those connections.  With the control logix, you not only get around double the connections available on most compacts, you can add additional cards to handle more connections.  If you are doing any advanced communications, or communicating with multiple network types then you will want to move up to the control logix or at least have a control logix system in your system design to act as a gateway to the various networks.