Allen-Bradley MicroLogix 1200 Reference Manual page 336

22-4 Data Logging (MicroLogix 1500 1764-LRP Processor only)
Publication 1762-RM001C-EN-P
Number of Records
Using Queue 0 as an example, each record consumes:
Record Field
Date
Time
N7:11
L14:0
T4:5.ACC
I1:3.0
B3:2
Integrity Check
Total
In this example, each record consumes 18 bytes. So if one queue was
configured, the maximum number of records that could be stored would
be 2730. The maximum number of records is calculated by:
Maximum Number of Records = Data Log File Size/Record Size
Example Queue 5
Table 22.2 Queue 5 (Time = , Delimiter = TAB)
Time
Record 0 20:00:00
Record 1 20:30:00
Record 2 21:00:00
Record 3 21:30:00
Record 4 22:00:00
Record 5 22:30:00
Record 6 23:00:00
String Length of Record
The size of a record is limited so that the length of the maximum
formatted string does not exceed 80 characters. The following table can
be used to determine the formatted string length.
Data
delimiter
word
long word
date
time
Memory Consumption
2 bytes
2 bytes
2 bytes
4 bytes
2 bytes
2 bytes
2 bytes
2 bytes
18 bytes
= 48K bytes/18 bytes
= (48)(1024)/18
= 2730 records
N7:11
TAB 2315 TAB
TAB 2400 TAB
TAB 2275 TAB
TAB 2380 TAB
TAB 2293 TAB
TAB 2301 TAB
TAB 2308 TAB
Memory Consumed
0 bytes
2 bytes
4 bytes
2 bytes
2 bytes
I1:3.0 I1:2.1
8190 TAB 4465
8210 TAB 4375
8150 TAB 4335
8195 TAB 4360
8390 TAB 4375
8400 TAB 4405
8100 TAB 4395
Formatted String Size
1 character
6 characters
11 characters
10 characters
8 characters