» Frequently Asked Questions NARDA PMM   AMB-8057-02

• During continuous monitoring measures on a SRB, carried out with two 8057-FUB,were detected very high values of the electric field and similar patterns . Then we decided to replace the two units with another (always PMM8055F) which showed the same problem as soon as the other was positioned in the measuring point. Since the measurements made with a broadband meter give very low values of the electric field (0.5 V/m), the only suspicious thing is the presence, near the units installation points, of a power line whose magnetic induction values are lower than 0.3 micro T.
  The firs two installed units once brought back to our office started to work again without any problem.
  Is it possible that the units are influenced by the electric field power line? And if so, for which intensity of the latter?
  
  50 Hz per se should not affect a WB measure of the unit at high frequency. But we may consider the following:
  
  - Let’s exclude the hypothesis that the unit can measure the harmonic power line, because to do this it should produce a high order (200 approx.). We do not know how this is possible, since CEI EN considers a maximum of 40 for calculating the THD (total harmonic distortion factor). We think, however, that there is the influence of the power line. In fact, analyzing the graphs we can see that:
  
  - the peak intensity are detected at the same time.
  
  - Those peaks take place at night. This is strange when you consider that in general the SRB have the best day when most users access the service.
  
  - Coincidentally, at least for the high voltage lines the maximum transfer occurs at night when the utilities do not require much electrically. One thing we noticed is that among the three units, the only one that detects reasonable values has the fully charged battery. In this case you can try to make acquisitions with fully charged batteries. The problem could arise from coupling on the supply side between power line/ unit. Do the units have a calibration certificate? less than 2 years? Could they be rechecked and recalibrated?

• I have a problem with two PMM 8057 units. Both of them when queried, either remotely or serial, give me a signal that is: Type mismatch. So the connection is closed and I cannot do anything. What should I do?
  
  Type Mismatch error appears when the date / time format of the control PC is not the correct one. The format is:
  Date: DD / MM / yyyy
  Time: HH: mm: ss
  also separators / e: must be corrected. The time format is 24 hours (no AM - PM).

• The graphs drawn directly from the program, the SW8057, allows you to highlight (with "Trace - Band GSM) data collected during the transmission of the GSM unit. This is the only way in which data is managed with an asterisk? In addition to their emphasis, it should be possible for the operator to choose not to include this data in the chart as it is not real I mean in environmental scenarios in which the fund is found close to the minimum value it does not make any sense that are kept two or more peaks in V / m that correspond only to the power and transmission unit. Ex: exporting data to obtain monthly charts, the only significant peaks are those due to the visible units.
  
  From the graphs directly elaborated by the program, the SW8057, allows you to highlight (with "Trace - Band GSM) data collected during the transmission of the GSM unit. This is the only way in which data is managed with an asterisk. Besides emphasizing them, it should be possible for the operator to choose not to include this data in the chart as it is not real.

• Is there a way to automatically clean up the txt file of the lines with asterisk or give the operator the chance to perform validation to assess the appropriateness of whether or not to maintain the row with the asterisk?
  
  you can decide whether to display the alarm GSM ON relating to the stored data. Just uncheck the option "GSM Band" from the Trace menu, click on Care "Save File Export Setup" and generate the report. This procedure does not delete files from the affected values. You can’t automatically produce purified txt file of the stored values corresponding to the activities of the GSM modem. Remember that settling the automatic turn off at the end of the modem connection minimizes the consistency of the GSM alarms.