IP258
21
After a few secnds the display will show the following.
SET SPAN 0
In sample 1 0
Press ENT to set
33.6dB 44.2dB
The bottom line of the display shows the attenuation caused by the sludge. During a desludge these readings will
fluctuate due to random variations in the sludge density. When the readings are reasonably stable press ENT at the
same time that a sample is taken. This will store the reading from the sensor.
SET SPAN 0
Span1 is now set 0
ESC to finish
↓ for Span2
Press the down arrow key to access the sample 2 and sample 3 screens (if required).
Repeat the above procedure for samples 2 and 3. The span is now set and ready for input of laboratory result (see
later). When the sample procedure is complete press ESC until the normal display shows.
For best accuracy the three samples should be taken over a period of approximately 2 to 3 minutes.
The samples should now sent for laboratory analysis to establish the actual suspended solids content.
When the laboratory analysis results are available, the span calibration can be completed by entering the solids
content (in % Solids) into “Lab Value 1” (P150).
If required, an estimated value can be used until the laboratory analysis results are available.
Note: Each time SPAN 1 is set the other two SPAN and LAB values are cleared and are not used
until new Span2 and Span3 calibrations are carried out. The MSM400 calculates the
average of all the valid span calibrations (a valid span calibration is one which has both a
span ‘N’ and lab val ‘N’ value). The calibrations must be carried out in numerical order
i.e. Span 1, then Span 2 and then Span 3. These values should be carried over a short
period of time i.e. 2 to 3 minutes.
6.5 AUTO CAL LAB VALUES
To complete the AUTO CAL the samples must now be analysed and the results entered into the lab value menu.
Access the LAB VALS menu by highlighting this option in the AUTOCAL menu and pressing ENT.
LAB VAL 0
LabVal 1 0
LabVal 2
LabVal 3
Highlight the number of the LabVal to be entered and press ENT
LAB VAL 0
LabVal 1 % 0
0.00 P150
Highlight the digit to be edited by pressing left or right arrows. To change the LabVal use the up and down arrows
until the required value is showing, then use left or right arrow to move on to next digit. The units of this parameter
are always % suspended solids. When the correct value is displayed press ENT to store the value. Repeat this step to
input LabVal 2 and LabVal 3 if required (please note that better accuracy is achieved if all three samples and
corresponding LabVals are entered). Press ESC until the normal display shows.
It is important to note that until the LabVal (1,2 or 3) are entered the system will use the default value of
attenuation for the calibration.