Crossbow

4 position control axes... position control axes are basic motion axes, and do not support group motions.  The instruction set in the manual shows which instructions can be used on a single axis positioning axis.

Not sure what bearing that has on anything... the task cycle time for the PLC primary task is the important value, and it is user configurable in Task Settings in Sysmac Studio.

The HMI already has a security system and if someone attempts to access a page that has security, it will prompt for a user name and password automatically. You need to set security for a page, and then create the users and assign them the proper security levels.

That entirely depends on the program in the PLC, and you will need someone familiar with programming to make any modifications.

If it has no lights at all, likely something has failed internally.  Most PLCs have at least a power LED that should be on.  Not familiar with that unit, but doesn't sound good...  

If you want a Mitsubishi solution, use SoftGOT.  It lets you create HMI screens and not have to buy the HMI.  You could also use any third party SCADA software that offers drivers for Mitsubishi.  Aveva, Ignition, IFIX, or a dozen others.

Not sure what you meant by 'the 10 input'.  But that's 2 digits.  BCD is 0-9 only.  So each group of 4 inputs MUST make a valid number 0-9.  K5X460 means 5 digits, X460-463, X464-467, X468-X46B, X46C-X46F, and X470-473 0001 through 1001 If for example your inputs are 1010, that's 10,  that's not legal for a single digit of BCD. Make sure the data on those 2 inputs makes 5 valid BCD values.

It's a programmable controller, you can program it to do anything you like. Every controller out there can do it, not just these...  Even a PC, it's all in the code you write... I've been asked to write exactly the same thing one, and I refused.

4100 is a generic operation error... in your case it has nothing to do with a memory card or a network... Look at the FIRST line of the error message... THE INSTRUCTION CANNOT PROCESS THE CONTAINED DATA.  When it gives you a program name and step number, it's a program error. The instruction it is highlighting is having an error with the input data... so what is put in via K4X460 does not work in the DBIN instruction... check the status of your inputs starting at X460 and see what it is trying to do.  And look at the help for DBIN to see what about it can cause the 4100 error.

Would it be easier to make a virtual axis, run motion commands on that, and use MC_GearIn and MC_GearOut to connect and disconnect the real axes to the virtual?  

There are options in Studio that allow you to inherit information from one project to another.  I personally have never used them, but that should allow you to make a master project and then make new projects by selecting parts of that master project.  I asked around, nobody has ever heard of an EXPORT function for XML, only the IMPORT from the IEC XML type.

GX Works2 and GX Works3 both had means to monitor buffer memory.  Haven't touched either in a number of years, so I forget the actual name of the window.

Global variables only. When you make the HMI variable on the Variable Mapping screen, it inherits the data format of the PLC variable.  Make sure you go to the Variable Mapping tab in the HMI project and map an HMI variable to the controller variables.  The HMI is a separate device, and has its own variable table.

Also check that you added your program to a task in Task Settings.  When you add new programs to a project (as you must have, since the default is a ladder program) you must go into Task Settings and assign it to a task like the primary task so that it executes.  The software doesn't assign them automatically.

You can save text data to files on the memory card. You can also send files to an FTP server.