Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 126)

Publication AG-UM008C-EN-P - February 2005
3-58 Configuring MicroLogix 1100/1200/1500 Controllers
Data Logging Data Logging is supported by the MicroLogix 1100 and MicroLogix
1500 LRP. It allows you to capture (store) application data as a record
for retrieval at a later time. Each record is stored in a user-configured
queue in battery backed memory. Records are retrieved from the
processor via communications. This section explains how Data
Logging is configured and used.
This section contains the following topics:
•
Queues and Records
•
Configuring Data Log Queues
•
DLG - Data Log Instruction
•
Data Log Status File
•
Retrieving (Reading) Records
Queues and Records
The MicroLogix 1100 controller has 128K bytes (128 x 1024) and the
MicroLogix 1500 LRP has 48K bytes (48 x 1024) of additional memory
for data logging purposes. Within this memory, you can define up to
256 (0 to 255) data logging queues. Each queue is configurable by size
(maximum number of records stored) and by length (each record is 1
to 80 characters). The length and the maximum number of records
determine how much memory is used by the queue. You can choose
to have one large queue or multiple small queues.
The memory used for data logging is independent of the rest of the
processor memory and cannot be accessed by the User Program. Each
record is stored as the instruction is executed and is non-volatile
(battery-backed) to prevent loss during power-down.