How Do I Create An I/O Table And Is It Necessary? - CX-Programmer

The PLC I/O table is necessary in the PLC to detail the configuration of the installed hardware and expansion units.
There are three versions of the I/O table. All three versions should have the same content in order to ensure a smooth operation.

The three versions are:
  • Current I/O table. The current hardware configuration of the PLC units and the slots at turning on the power supply.
  • Registered I/O table. The internal PLC table, this table is used during the running of the PLC, regardless of the status of current hardware.
  • CX-Server I/O table. The configuration is known in CX-Server. These I/O table can independently of the PLC be directly created or modified and can be downloaded to the PLC with CX-Programmer (see below). You can upload  the I/O table of the PLC using CX-Programmer.

If for some reason the three versions are not identical, then it is possible that the PLC unit will not display them correctly.

The I/O table in CX-Programmer

The I/O table is displayed in a hierarchical structure.
All possible shelving and unit numbers will be displayed, even though they may not be in use. The I/O modules that are still to be completed are at the end, displaying every input and output characteristic for the module.
When a Remote Master is completed, then the structure can be further expanded to include the displayed slaves.
The I/O Table itself

By double-clicking  you'll have a list of available modules. You display information about the selected unit by clicking on it. Choosing the  (OK button) allocates the slot number to the type of module. It is also the starting address of the selected unit.
If you choose a communication or a special I/O unit, eg an analog input unit, the unit can be setup by setting the number and unit. This only lasts for when it is off-line, otherwise the unit is already present. CX-Programmer than an error. This is done by the unit in the I/O table, double click.

For more information, W437, CX-Programmer Operation Manual and special I/O units associated manuals.


The automatic creation of an I/O table

Under Options are located the Transfer choices.
Creating one with the PLC automatically creates an I/O table. 
The three identical I/O tables should then be visible in CX-Programmer.

Obviously, the communications units set up  and special I/O modules should still take place.


See also Creating An I/O Table On A CJ1 PLC