1766-RM001A-EN-P MicroLogix 1400 Programmable Controllers ...

518 Recipe and Data LoggingData LoggingData Logging allows you to capture (store) application data as a record forretrieval at a later time. Each record is stored in a user-configured queuein battery backed memory (B-Ram). Records are retrieved from theMicroLogix 1400 processor via communications. This chapter explainshow Data Logging is configured and used.This section contains the following topics:• Queues and Records on page 518• Configuring Data Log Queues on page 523• DLG - Data Log Instruction on page 525• Data Log Status File on page 526• Retrieving (Reading) Records on page 528Queues and RecordsThe MicroLogix 1400 processor has 128K bytes (128 x 1024) of additionalmemory for data logging purposes. Within this memory, you can defineup to 256 (0…255) data logging queues. Each queue is configurable bysize (maximum number of records stored), and by length (each record is1…109 characters). The length and the maximum number of recordsdetermine how much memory is used by the queue. You can choose tohave one large queue or multiple small queues.The memory used for data logging is independent of the rest of theprocessor memory and cannot be accessed by the User Program. Eachrecord is stored as the instruction is executed and is non-volatile(battery-backed) to prevent loss during power-down.Program Files23456 to 255Data Files01234 to 255Function FilesHSCPTOXPWMXSTIEIIRTCSpecialty FilesQ0Q1Q2Q3Q4 to 255Publication 1766-RM001A-EN-P - October 2008