Chapter 12

Processor Data Organization

Objectives (1 of 2)

• Describe a processor file.

• Explain what two files make up a processor file.

• Explain the function of a program file.

• Explain the function of a data file.

• List the contents of a program file.

• Explain the contents of a bit file.

Objectives (2 of 2)

• Explain how a bit file is made up.• Explain the contents and makeup of an

integer file.• Explain what an element and a sub-element

are. • List which instructions have multiple word

elements.• Describe what status bits are and where they

are used.

Project File Terms (1 of 2)

• Project– The collection of the ladder program and all

associated information

• Processor file– Contains all information that is downloaded

into the processor• The processor file contains program files and data

files.

Project File Terms (2 of 2)

• Program files– Program files are ladder files. – The SLC 500 can contain up to 256 ladder files.

• Data files– Data files contain data associated with the ladder

file(s). – The SLC 500 can contain up to 256 data files.

• Database files– Database files contain ladder documentation file data.

RSLogix 500 Project Tree (1 of 2)

• The RSLogix 500 software stores all project files in the project tree.

• File is a group of related elements.

• Project tree is similar to a table of contents.

RSLogix 500 Project Tree (2 of 2)

Processor Memory Is Like a Two-Drawer File Cabinet

Program Files in Their Separate File Drawer

Data Files Stored in Their Separate Drawer

SLC 500 Default Data Files

• When a new project is created, the software creates data files 0 through 8.

• Each file has a file identifier and a file number.

• A file is a group of related elements.

• The file identifier and file number make up part of the data stored in the file’s address.

SLC 500 Default Data Files (1 of 2)

SLC 500 Default Data Files (2 of 2)

• Each file contains specific information needed by the processor in order to complete its job of executing the user ladder program.

• Default data files are organized as follows:

File 0, Output Status File (1 of 2)

• Made up of single bits grouped into a 16-bit word– Each bit represents the ON or OFF state of

one output point.– There is one output word reserved for each

output module in your SLC 500 system.

File 0, Output Status File (2 of 2)

• File identified as file O.

• Bit identifiers across top of file represent discrete output screw terminal designation.

• Address format O:2.0.– O identifies output file type.– 2 identifies output module in chassis slot 2.– .0 identifies word zero.

SLC 500 Output Status File

File 1, Input Status File (1 of 2)

• Made up of single bits grouped into a 16-bit word.– Each bit represents the ON or OFF state of

one input point.– There is one input word reserved for each

input module in your SLC 500 system.

File 1, Input Status File (2 of 2)

• File identified as file 1.

• Bit identifiers across top of file represent discrete output screw terminal designation.

• Address format I:3.0.– I identifies output file type.– 3 identifies input module in chassis slot 3.– .0 identifies word zero.

SLC 500 Input Status File (1 of 2)

SLC 500 Input Status File (2 of 2)

• Only words in the output and input status files are created for I/O modules that actually exist in the SLC 500 system.

• Output and input status file word creation is part of the I/O configuration process.

B3, Binary, or Bit File

• The binary or bit file stores single-bit data.

• Binary file also referred to as an internal coil, internal relay storage.

• Internal bits are used to store internal data.

• Identified as file B3.

Each Bit File Element Consists of One 16-bit Word

T4, Timer File

• The timer file stores only timer elements.• An element is a word or group of words that work together as a

unit.• A timer is made of three pieces or words.

– Preset value– Accumulated value– Status bits

• The preset value and accumulated value are 16-bit signed integers.

• Status bits are single bits that make up one 16-bit word.• These three words work together as a unit.

One Timer Element Is Made of Three 16-bit Words

Timer Addressing

• Sample timer element addressT4:2– T4 = timer file 4– :2 = timer element #2 (0-255 timer elements

per file)

Sub-Element

• A sub-element is part of an element addressable as a unit.

• The preset value and accumulated value are sub-elements of a timer.– T4:0.PRE– T4:0.ACC

Timer Status Bits

• Timers have three status bits.

• Done bit (DN) is true when the accumulated value and preset are equal.

• Timer timing bit (TT) is true when the timer is timing.

• Enable bit (EN) is true when the timer instruction is enabled or true.

Timer Bit Addressing

• Status bit addresses for timer file 4, timer element 2 (T4:2) are listed below:– T4:2/DN is the address for the done bit.– T4:2/EN is the address for the enable bit.– T4:2/TT is the address for the timer timing bit.

Timer File T4

C5, Counter File

• The counter file stores only counter elements.• An element is a word or group of words that work together as a

unit.• A counter is made of three pieces or words:

– Preset value– Accumulated value– Status bits

• The preset value and accumulated value are 16-bit signed integers.

• Status bits are single bits that make up one 16-bit word.• These three words work together as a unit.

One Counter Element Is Made of Three 16-bit Words

Counter Addressing

• Sample counter element address C5:2– C5 = timer file 5– :2 = counter element #2 (0-255 timer

elements per file)

Sub-Element

• A sub-element is part of an element addressable as a unit.

• The preset value and accumulated value are sub-elements of a counter.– C5:0.PRE– C5:0.ACC

Counter Status Bits (1 of 2)

• Counter has five status bits.

• Done bit (DN) is true when the accumulated value and preset are equal.

• Count up enable bit (CU) is true when the up counter is true or enabled.

• Count down enable bit (CD) is true when the count down counter is enabled or true.

Counter Status Bits (2 of 2)

• The overflow bit (OV) is true when the up counter has overflowed above +32767.

• The underflow bit (UN) is true when the down counter has underflowed below -32768.

• The update accumulator bit (UA) is a high-speed counter status bit for fixed SLC 500 PLCs.

Counter Status Bit Addressing (1 of 2)

• Status bit addresses for counter file 5, counter element 0 (C5:0) are listed below:– C5:0/DN is the address for the done bit.– C5:0/CU is the address for the count up

enable bit.

Counter Status Bit Addressing (2 of 2)

– C5:0/CD is the address for the count down enable bit.

– C5:0/OV is the address for the count up overflow bit.

– C5:0/UN is the address for the count down underflow bit.

Counter File C5

R6, the Control File

• The control file is used to store status information for – Bit shift– First-in and first-out stacks (FIFO)– Last-in and first-out stacks (LIFO)– Sequencer instructions– Certain ASCII instructions

One Control Element Is Made of Three 16-bit Words

N7, Integer File

• The integer file stores a 16-bit signed integer representing a whole number.

• Integer file data range –32,768 to +37,767.

• Integer file has no status bits.

• Each integer file can have 0 to 255 integer elements.

Integer File Element Consists of 16-bit Elements

F8, Floating Point File

• Storage of fractional numerical data or values greater than 32767

• Data range of 1.1754944e-38 to 3.40282347e+38

• Floating point file is processor operating system dependent

• Must have 5/03 modular processor with OS 301 or above, 5/04 or 5/05 processor

Floating Point File Data Representation

User-Defined Data Files (1 of 2)

• Default files are data files 0 through 8.

• Total of 256 data files if processor will support them.

• Each data file can have up to 256 elements if processor supports them and has enough memory.

• Files greater than file number 8 are user-defined files.

User-Defined Data Files (2 of 2)

• User-defined files are data files the user can create and define as needed for specific applications.

• They cannot create additional output, input, or status files.

SLC 500 User-Defined Files

Review of SLC 500 Data Files