Allen-Bradley ClutchBrake PLC-5 Series - Working with Data; Types of Data; Addressing Your Data

Programming Considerations for PLC-5 ProcessorsF–10
Publication 65566.5.1 - October 1996
Understanding the types of data that your processor handles and how
your processor stores them may help you:
• conserve memory
• achieve a faster processor data scan
Types of Data
The types of data that your processor handles depend on the processor,
but essentially falls into three categories: bit, word, and element.
Data are stored in files, which are blocks of data of similar type.
Some types of data can be stored in more than one type of file.
Each type of file has an ID letter to identify it in an address.
Type of Data Description Type of File File ID
bit smallest unit of data: 0/1, on/off, set/reset bit
I/O image
B
I or O
word 16 bits: can represent a numeric value,
such as with binary coded decimal (BCD)
For example: 0000 0000 0000 0110 = 6
I/O image
status
integer
I or O
S
N
element a multiple number of words
For example: timer element = 3 words
(preset, accumulated, control/status bits)
timer
1
counter
1
control
1
T
C
R
1
Each timer, counter, or control element uses three words
Addressing Your Data
Logical address formats (Figure F.4) vary depending on the type of
data. Addresses contain these characters:
• file type (ID)
• file number
• delimiter to separate address numbers
• number (location) of the structure, word, bit, and/or I/O hardware
Figure F.4
Typical
Address Formats
N7:15T4:7.ACC
B3:64/15
File Type ID
File Number
Word/Structure Number Word or Element Number
Bit Number
Delimiter
File Type ID
File Number
Member Number
Delimiters
File Type ID
File Number
Word Number
Delimiters
Address for Wordtype DataAddress for Structuretype Data Address for Bittype Data
O:002/15
Terminal
N
File Type ID
2digit Rack Nu
Delimiters
Address for I/O Image D
a
I/O Group N
u
Working With Data