The error code "2100" is "SP.UNIT LAY ERR.". This error may be caused by one of the following factors.

 (1) In the I/O assignment setting of the PLC parameter, an I/O module is assigned as "Intelli."
       (intelligent function module), or vice versa.

 (2) In the I/O assignment setting of the PLC parameter, the CPU module is assigned as another type of module or "Empty",
       or vice versa.

 (3) In the I/O assignment setting of the PLC parameter, the number of points assigned to the intelligent function module is less 
       than the number of points of the connected module.

As a remedy, set the I/O assignment again in the I/O assignment setting of the PLC parameter, so that the setting matches with
the mounted status of the intelligent function module or the CPU module.