Veris Technologies MSP EC and pH (1997-2008 CF card drive 1.10M) - Operating Instructions User Manual
Page 38
Veris Technologies
Pub. #OM MSP03-1
38
Exiting Data Acquisition and Extracting pH Data
When you are ready to stop collecting pH data to the file, press 1. Wait for the unit to finish its current
cycle and for the PRESS 1 TO START message in the controller message area before pressing 4 to
exit data acquisition.
The instrument will now extract the final pH points from the raw data collected during data acquisition:
After the extraction process is complete, the instrument will display the extracted file statistics:
Under normal operations, it is common for 10% of the points to be rejected. If a higher percentage is
rejected, recalibrate electrodes and inspect wash system. NOTE: all pH data including the rejected
points remain in the raw data file ((VPHL000.DAT) and can be post-processed. If an electrode failed
during mapping and the operator didn’t detect the problem, most of the points would be rejected. Yet
the measurements from the working electrode can be post-processed from the raw data file.
Looking at the average settling time helps identify sluggish electrodes.
SD= standard deviation of pH. The average pH and the pH SD are early indicators of the economics
of VR lime. Generally, fields with an average pH <6.5 and an SD >.4 are candidates for VR lime.
If the field has been mapped using a double-back method (returning to the starting point), comparing
the starting and ending averages will show any drift in the pH electrodes.
A more detailed report is located at the bottom of the extracted file (see the example extracted file for
details). Press any key for the following screen:
The instrument saves all data during data acquisition simultaneously to the instrument’s built-in flash
memory and the removable CF card.
About the Veris pH output file formats: 3 files are created during pH data acquisition: one
containing the raw millivolt readings of the electrodes in soil (VPHL000.DAT), one containing the
millivolt readings of the electrodes during the wash sequence (VPHW000.DAT), and one containing