| Installation, Operation & Maintenance Manual |
MSL600 | IP262/Z0, Rev. AB |
February 2012 | |
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7.9.3Municipal 1 parameters P630 to P637
When the Municipal 1 algorithm is selected using parameter P620 (page 37), only the following specific parameters need to be adjusted.
7.9.3.1Significance – P630
This parameter is used to select which echo in the echo profile that the Municipal 1 algorithm chooses as the most likely to correspond to the real sludge blanket level.
The algorithm scans the echo profile for echoes. It calculates the mean and standard deviation of amplitudes for these echoes. Depending on the P630 setting, the algorithm can be programmed to select the first significant echo it comes to, measured from the surface of the supernatant or the most significant echo it detects in the entire profile.
The allowed options are:
•First
•Most (default)
7.9.3.2Sharp Echo Reject – P631
Electrical noise and other types of false echo are characteristically shorter in duration than the real echo from a sludge blanket. This parameter allows fine tuning of the value which the municipal algorithm uses as a window width to separate out these echoes.
Note:
This is a key system parameter and should not be adjusted without asking for advice from Mobrey Measurement.
Parameter values:
Default | Min | Max |
8 | 5 | 30 |
7.9.3.3Lost Echo Rnge - P633
The lost echo range is the distance, split equally above and below, that the device will still look for an echo before going to hold last reading as set in lost echo delay (P637).
The parameter P633 is set in number of samples. However, each sample equates to approximately 25mm (1”). Therefore when set with the default value of 24, the device will look for a valid echo in a window 300mm (12”) above and 300mm (12”) below its last valid value. If no valid echo is present, it will hold its last reading for the programmed amount as set in P637.
Parameter values:
Default Min Max
241410
7.9.3.4Threshold – P634
The Municipal 1 algorithm scans the echo profile for echoes. It calculates the mean and standard deviation of amplitudes for these echoes. In order to be significant, the echoes must exceed a threshold value determined in terms of the standard deviation of the echo amplitudes.
The default value is 0.5 standard deviations.
Parameter values:
Default | Min | Max |
0.5 | 0.00 | 9.99 |
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