Mycom S CLM 153
6 Commissioning
Hauser
41
6.4.7
Set up 1 – Concentration
The transmitter can convert conductivity values to concentration values. To do so, you
must first switch the operating mode to concentration measurement (s. page 31, Field
A1).
Then select the basic data to which the concentration measurement should refer. These
data are already stored in the transmitter for the most common substances. You can
select one of these substances in Field A3 / AA1.
You can also determine the concentration of a sample which is not stored in the device.
For this, you require the conductivity characteristics of the medium. To get the
characteristics, you can either
refer to the data sheets of the medium or
determine the characteristics your self
.
1.
To do so, create samples of the medium with the
concentrations occurring in the
process
.
2.
Measure the uncompensated conductivity of these samples at temperatures which
likewise occur in your process.
–
For variable process temperature
:
If the variable process temperature should be taken into account for
concentration measurement, you must measure the conductivity of each sample
created at two different temperatures at least, (ideally at the lowest and highest
process temperature). However, the difference between the temperatures must
be at least 0.5 °C. A minimum of four samples is necessary, since the transmitter
requires a minimum of four references.
–
For constant process temperature
:
Measure the differently concentrated samples at this constant process
temperature. Again, a minimum of four samples is necessary for four references.
Finally you should have measuring data which are similar to those shown in the following
illustrations:
Impermissible curve profiles
The characteristics received from the
measuring points must be extremely
monotone increasing or extremely
monotone decreasing in the range of the
process conditions. Therefore, neither
maxima / minima nor ranges with a
constant behaviour can occur. Curve
profiles such as those in fig. 16 are not
permitted.
Fig. 16:
Impermissible curve profiles
Conductivity
Concentration
Conductivity
Concentration
C07-CLM153xx-05-06-00-en-006
