5 The files saved on the SD card

5.1 The MUX log files

All activities from the MUX are saved on a file named YYMM-MUX.txt, with YY for the year, and MM for the month. A typical example of the content of the MUX.txt file is illustrated below:

2019/7/4 10:32:36, 10, Forward, 10, 20, 5, Automatic - Start!
2019/7/4 10:33:06, 8, Reverse, 10, 20, 5, Automatic
2019/7/4 10:33:12, 2, Forward, 3, 15, 3, Automatic
2019/7/4 10:33:30, 2, Reverse, 3, 15, 3, Automatic
2019/7/4 10:35:35, 1, Forward, 15, 10, 8, Automatic
2019/7/4 10:36:00, 8, Reverse, 15, 10, 8, Automatic
2019/7/4 10:36:09, 2, Forward, 3, 20, 3, Automatic
2019/7/4 10:51:36, 10, Forward, 10, 20, 5, Automatic - Start!
2019/7/4 10:52:06, 8, Reverse, 10, 20, 5, Automatic
2019/7/4 10:52:12, 2, Forward, 3, 2, 3, Automatic
2019/7/4 10:52:17, 2, Reverse, 3, 2, 3, Automatic
2019/7/4 10:52:20, 7, Forward, 3, 2, 4, Automatic
2019/7/4 10:52:25, 3, Reverse, 3, 2, 4, Automatic
2019/7/4 10:53:36, 1, Forward, 15, 15, 8, Automatic
2019/7/4 10:54:06, 8, Reverse, 15, 15, 8, Automatic
2019/7/4 10:54:15, 2, Forward, 3, 2, 3, Automatic
2019/7/4 10:54:20, 2, Reverse, 3, 2, 3, Automatic
2019/7/4 10:54:23, 7, Forward, 3, 2, 4, Automatic

On each line of the file, the first value is the time stamp of any pumping (Forward) or purging (Reverse) action. The next value is the valve or port that is activated. The next value is whether the pump pumped forward or purged for purging. The next three values correspond to . The next value tells whether the MUX actions were automatic, or whether the pumping and purging were done manually. When the MUX is started by turning the on/off button, or when the MUX is automatically reset at midnight, these actions are flagged by a ‘- Start!’ at the end of the line.

This log file is very useful when trouble shooting and to corroborate information stored on the .fp file.

5.1.1 The fingerprint files

The fingerprint files are a copy on the SD card of the fingerprint (.fp) stored by the Spectro::lyser. Until very recently, there was very limited memory space on the Spectro::lyser, leaving about three days of autonomy for 3-min measurements… As a result, the MUX automatically interrogates the Spectro::lyser after each sampling sequence and asks the Spectro::lyser to give the last absorbance spectrum stored in its memory, and appends it at the end of an .fp file on the SD card.

An example of the such .fp file is illustrated below. The first line defines which Spectro::lyser is used. The second line defines the Date/time, then status (OK or not), and then the wavelengths at which the absorbances are measured. In our case here, from 200.00 to 750.00 nm. The next lines provide the Spectro::lyser time stamp, the status of the probe, the absorbance values corresponding to each wavelength, AND, at the end of the line, the valve used for pumping and the time stamp from the MUX. The ... replace all the 200 and some intermediate values on each line.

17240013_50_0x0101_spectro::lyser_RIV100NFV2
Date/Time   Status_0    200.00  202.50  ... 745.00  747.50  750.00
2019.07.04  10:51:59    Ok  42.7532 41.6454 ... nan nan nan 10  19/7/4 10:52
2019.07.04  10:51:59    Ok  42.7532 41.6454 ... nan nan nan 1   19/7/4 10:54
2019.07.04  10:53:59    Ok  42.8591 41.7240 ... nan nan nan 3   19/7/4 10:56

There is an identified bug, which we have not resolved satisfactorily on an automatic basis, yet. However, when aware of it, it can be easily resolved manually. At the end of its sampling sequence, the MUX inquires about the last measurement stored by the Spectro::lyser. In the meantime, in the Spectro::lyser sequence of actions (Figure 3.2), the time for analysis of the measured absorbance takes about 25 seconds. If the inquiring time, the Spectro::lyser has not finished analyzing its results, then the absorbance spectrum available on the Spectro::lyser memory is NOT the current measurement, but rather the previous measurement. This is illustrated in the .fp exert above. The fingerprint time stamp and values are exactly the same in third and fourth line of the file, although the MUX time stamp at the end of the lines have changed. This is because on the 10:54 measurement, the Spectro::lyser was still analyzing its measurement, and the available fingerprint on memory was the previous one. It is relatively easy to manually reassign the correct fingerprint to the correct port.

Now, when the end of the sampling sequence occurs after analysis of the Spectro::lyser, then the fingerprint available in the memory is the one corresponding to the MUX time stamp. In these cases, the Spectro::lyser fingerprint and MUX time stamps are synchroneous.

The naming conventions for the .fp files are YMMDDlettermm.fp. The letter a is used for 0 hour, and x for 23 hours. The hour corresponds to the hour at the time when the file was created.