Data Logging; Data Storage - Advanced Power technologies TTC-1000 Instruction & Operation Manual

11 DATA LOGGING

Data logging permits storage of time stamped temperature and load data. The
user has the ability to change the time base used for time stamping from 1 to
9999 seconds. Setting the time base to zero erases the log and prevents records
from being recorded. The user can select which points to record. Points which
can be recorded include probe P1's temperature, P2's temperature, calculated
winding temperature, and load. Once the log is full, the oldest records are over
written with the newest records. Since the records are stored in non-volatile
memory, records are never lost even in the event of a power interruption.

11.1 Data Storage

There are 32,512 bytes available for storage of data records. A byte is defined as
an 8 bit quantity. Each record is time stamped at an interval defined as the Time
Base. A data record is defined as a set of data points. Data points can include
probe P1's temperature, P2's temperature, P3's temperature, calculated winding
temperature, and load. All temperatures are stored as a single byte. Load is
stored as a two byte quantity. There are two additional bytes per record to assist
the firmware in storing and retrieving the data log. A record can be anywhere
from 3 bytes to 8 bytes in length. The following table summarizes the available
data points and the maximum number of records that can be stored:
Points Recorded
P1, P2, P3 or Calculated Winding
Any two temperatures
Load
Any one temperature and Load
P1, P2, P3, and Calculated Winding
Any two temperatures and Load
All three temperatures and Load
All three temperatures, Winding and Load
Table 11.1: Maximum Records
After selecting the data points to log, it is simple to figure out the length of time
data can be recorded. For example if 30 minutes time stamping is required, Time
Base=1800, and all four points (P1, P2, Winding & Load) are required, the
maximum time that data can be recorded in days is equal to 4,644 divided by 48
records per day or 96 days. This can be extended to up to 1254 days if only one
temperature is recorded every 9999 seconds or ~2.75 hours. Practically
speaking, a temperature and load will be logged every hour or 3600 seconds. In
this case the log will hold 270 days of data.
There is one limitation, in the event that power is interrupted, the time stamp is
stored as a data record. Time stamp records consume a total of 8 bytes. This is a
Bytes/Record
3
4
4
5
6
6
7
8
111
Max Records
10,837
8,128
8,128
6,502
5,418
5,418
4,644
4,064
V6.70 20131017