Measurement Computing USB-5203 - Manual (Page 20)

USB-5203 User's Guide Functional Details
20
Calculating the logging time for a memory card
Use the following formula to calculate the approximate amount of logging time in seconds that one of the
supported memory card allows. The USB-5203 supports 512 MB , 1 GB, and 2 GB CompactFlash memory
cards.
where
 time = total disk time in seconds
 N
Disk
= size of memory card in bytes
 N
DIO
= 1 byte for digital I/O
 n
Channels
= number of channels logged
 R = logging rate in seconds
 N
TS
= 6 bytes for timestamp, if enabled
 N
Temp
= 4 bytes for a temperature reading
 N
CJC
= 8 bytes if CJC sensor readings are
enabled
The following table provides examples of logging one channel and eight channels of temperature readings at the
max logging rate of 1 S/s to a 512 MB memory card with DIO, timestamp, and CJC sensor logging enabled:
Memory card
(bytes)
DIO enabled Number of
channels
Logging
rate (S/s)
Timestamp
enabled
Temperature
reading
CJC
enabled
512,000,000 1 1 1 6 4 8
512,000,000 1 8 1 6 4 8
Data logging button
Use the data logging button to end a data logging session. The data logging button is also used to start recording
data when the logging mode is set in InstaCal to Start Logging on Button.
 To begin recording data, press and hold the button until the LED begins to blink. The first sample is taken
one second after the LED illuminates.
When you first power on the USB-5203, wait at least five seconds before pressing the data logging button.
To achieve rated accuracy, allow the USB-5203 to warm up for 30 minutes before logging data.
 To stop recording data, press and hold the button again until the LED is off.
Caution! To prevent loss of data, always use the button to stop logging. Make sure the data is written to the
memory card before you disconnect the device from the power source.
The device caches log data in volatile memory prior to writing to the memory card.
Pressing the data logging button has no effect when the USB-5203 is connected to an active USB port and not
logging data.
External power required for data logging
Due to processing limitations, data logging is not allowed when the USB-5203 is attached to an active USB bus.
The USB-5203 must be connected to the standalone power supply to perform data logging.