Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 104)

Chapter 6
Programming Overview
6–7
Power Up
During power up, the micro controller transfers the program files from the
EEPROM to the RAM. The retentive data is also transferred to the RAM,
provided it was not lost on power down, and normal operation begins.
CPU
EEPROM
Backup Data
Retentive Data
Program Files
RAM
CPU Workspace
Retentive Data
Program Files
If retentive data was lost on power down, the backup data from the EEPROM
is transferred to the RAM and used as the retentive data. In addition, status
file bit S5/8 (retentive data lost) is set and a recoverable major error occurs
when the mode is changed to RRUN, RCSN, or RSSN.
CPU
EEPROM
Backup Data
Retentive Data
Program Files
RAM
CPU Workspace
Retentive Data
Program Files
For the purposes of addressing, each data file type is identified by a letter
(identifier) and has an associated allowable range for data storage.
Output
Input
Status
Bit
Timer
Counter
Control
Integer
O
I
S
B
T
C
R
N
File
Type Identifier
0
1
32
31
39
31
15
104
Allowable Word Range, 0 to:
Discrete Analog
4
7
–
–
–
–
–
–
The addresses are made up of alphanumeric characters separated by
delimiters. Delimiters include the slash and period.
Addressing Data Files