Span Calibration - Toshiba LQ300A00 Series Operation Manual

(15) Restoring to the measuring mode
Press the [ESC] key of the converter twice to return the menu of the LCD indicator to the initial
menu display to return to the usual measuring mode from the setting mode. Thus, the
measurement starts.
◆ In the event that the external synchronized operation is selected, the external contact input
signal is changed to ON, thus starting the density measurement after the specified delayed
time has elapsed.

6.5 Span Calibration

Span calibration is for adjusting the readings of the density meter to the values determined by manual
(off-line) analysis.
For information on the converter operation and the LCD display regarding span calibration, please refer
to Subsection 5.2.12.
(1) Preparations for manual analysis
Prepare following items for manual analysis; a moisture meter (for example, an infrared moisture
[NOTE]
meter, with the accuracy or percentage reading down to 0. 1 %), plastic bottles of about l liter
with a wide opening, and plastic beakers of about l00 ml for manual analysis.
(2) Sample fluid for manual analysis
Slightly open the sampling valve on the pipeline and let out the fluid a while before filling a 1-
liter bottle to half. Read and record the density value of the current fluid.
◆ Make sure to carry out the sampling when the density of the measured matter is in a stable state with the
measured matter flowing.
(3) Manual analysis
Put a part of the sample fluid into a 100-ml plastic beaker, and measure the density of it using
drying and weighing method of analysis.
(4) Calculation of density multiplier
Use the result of analysis to calculate a density multiplier using the following equation after the
manual analysis conducted:
Density multiplier C = A/(M/C
(Initially, C
For example, if M = 4.0 z%TS, A = 4.8 %TS and C
◆ In the case that span calibration has been done already, and density multiplier C is not 1.000,
the new density multiplier C can be calculated in the following way.
For example, if M = 4.8 %TS, A = 4.2 %TS and C0=1.2
where M is the density by the density meter (as read and recorded);
A is the result of the manual analysis
'
C is the density multiplier before span calibration
'
is equal to 1.000 which is the value set in the factory before shipping)
C = 4.8 / (4.0/1) = 4.8/4.0 = 1.2
C = 4.2 / (4.8/1.2) = 4.2/4 = 1.05
'
)
'
=1.000
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