On-Line And Off-Line Recordings; Memory Capacity During On-Line And Off-Line Recordings - Intab PC-Logger 2100 User Manual

1.1

On-line and Off-line recordings

PC-logger 2100 can make recordings in two different ways: On-line and
Off-line.
An On-line measurement is performed with the computer connected to the
logger during the entire recording. Measured data are continuously transferred
from the logger to the computer and stored on disk.
During the recording it is also possible to analyse/evaluate the measurements in
real-time on the computer screen. You can also analyse previously acquired
recordings while the current recording is taken care of in the background.
An Off-line recording should be initiated by transferring measurement
parameters from the computer to the logger. These parameters tell the logger
how to perform its recording and contain information about: interval, active
channels, channel configuration, etc. (See also software manual.) All parameters
are valid until a new set is transferred.
The PC-logger can then, after the parameters have been transferred, be
disconnected from the computer. The recording is started using the keys on the
logger itself. During the recording, the data is stored in the logger's internal
memory which has a capacity of appr. 110.000 values.
When the recording is completed the logger is again connected to the computer
for transferral of collected data to disk.
1.2

Memory Capacity during On-line and Off-line recordings

Every stored sample occupies 2 bytes of memory.
When making On-line measurements, it is the amount of free space on the
computer's disk (floppy disk or hard disk) that limits the length of the recording.
For an Off-line recording the limiting factor is the internal memory capacity of
the logger. This memory of 224k Bytes can hold 112 000 values.
The parameters that affect the maximum recording length (or duration) are:
Sampling Interval, Reduction Factor (Averaged Value), Number of channels
used and of course if it is an On-line or Off-line recording.
When using Intab's software, the user is always informed of how long the
recording can last while entering the various parameters.
Example: Off-line-recording.
The PC-logger can sample on 8 channels, 10 times each hour during 2 months.
(0,1 x 224.000) / (2 x 8) = 1400 hours! (58 days)
Please note that the PC-logger only can handle one recording at a time. If an
Off-line recording is started before the previous Off-line recording was
transferred to disk, the first one will be lost!
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INTAB Interface-Teknik AB, Sweden