Servomex NanoTrace DF-760E, Instruction Manual

Page: 59 / 182

User Interface DF-760E 55
time, the AutoZero is automatically aborted and the Fail Zero flag is set in the Zero Cal
Log as shown in Figure 38.
The system provides warning of a scheduled AutoZero (preceded by a pre-zero purge if
any) before the calibration takes place, according to the time set in the
Pre-Zero Warning
.
The
Pre-Zero purifier purge
enables the user to set an amount of time from 1 to 200
hours during which the system will be purged with zero gas before the AutoZero process
begins. This is useful for gases such as oxygen that take a long time to equilibrate. When a
non-zero number is entered in this field, a separate purge count down is added to the auto
zero screen and this time is also automatically added to the timeout.
The
Zero Acceptance Criterion
allows the user to select the stability criteria required
before the zero value is accepted. The Stable selection (recommended) ensures the most
accurate zero calibration but takes the longest time to execute (68 minute delay before the
zero process begins). The Quick selection takes the least time (17 minute delay) and as a
result is the least precise. The Normal selection applies an average of the two (34 minute
delay).
A relay is available on the Moisture Analog Output Setup Screen (see page 66) to signal
that a zero calibration is taking place, and the analog output signal can also be frozen or
allowed to update during the calibration process.
7.5.3 Moisture Data History Routine
Figure 28: Moisture Data History
The Data History Screen (Figure 29) enables the user to see the data history displayed in
strip chart form on the front display. By default, the data history screen displays data for
the most recent 24 hour period sampled at a rate of 1 point per minute (fixed) and the y-
axis is auto-scaling. Note, the Data History Screen is also accessed from the Data
Downloader screen (Figure 33).
The Next button can be used to toggle the X axis scale from 1 day (default), to 1 hour, to 1
week or to 3 weeks. The
Next
button can also toggle the cursor to the max and min values
on the Y axis. The arrow keys ( and

can then be used to adjust the values, and the
display will actively update.
The data history may be downloaded to a USB memory stick ( Flash Drive) by using the
Next key to move to the Download box and hitting Enter. A screen will appear, (see