Thursday, July 7, 2011

User Data Memory of Modicon Micro PLC

The PLC transmits each signal of input and output in the control process to a position number that is saved in a memory table of user data and can be applied in the ladder logic program. The PLCs of 110CPU311 and 110CPU411 have 512 words of user data memory PLCs of 110CPU512 and 110CPU61200/03 have 2048 words of user data memory PLC of 110CPU61204 has 8192 user data memory words.

Note The buffer of execution in the 61204 is large enough to run the XMIT and/or Gas loadable without dropping the 8K of existing user logic.

Reference Numbering
The PLCs of Modicon Micro utilize a system of reference numbering to handle input/output internal logic and information for ladder logic programming. Every orientation number has a leading digit that specifies the I/O data type; the leading digit is tracked by a string of four digits that identifies that unique I/O point’s location in the user data memory. Every word in the memory of user data is 16 bits long. The ON/OFF state of every discrete I/O point is corresponded to by the 0 or 1 value allocated to each bit in a word.

System Configuration Memory
The configuration of PLC is a key point of overhead included in system memory. The information included in the configuration decides such things as: The PLC operating mode, the parameters under which the PLC’s communication ports can function. The available ranges are 0x, 1x, 3x, and 4x positions existing for programming, the I/O locations number supported by the PLC

Note The 61204 needs Modsoft Lite, or Modsoft version 2.5 or up. You can admission the configuration and identify a lot of these parameters with your panel software programming.

These defaulting values create use of all the memory existing for PLC setup. You may duplicate pieces of configuration memory system to ensemble the I/O specifications in a specific application. For instance, if you are applying a 110CPU31101 PLC and the application needs 35 register inputs in its place of the defaulting 32 registers, you could relocate the additional three words from somewhere else in the setup table. State the appliance does not need all 1024 discrete outputs—you can identify 976 discrete outputs in the setup table of PLC, after that modify the additional 48 bits as the three 16-bit of additional input register words.

Note The total memory amount constructed for PLC setup cannot go over the values sum of the Default PLC setup values.

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