Commissioning
68
7.6.6
Set up 1 - Temperature
The pH value requires temperature compensation for two reasons:
1.
Temperature effect of the electrode:
The slope of the electrode depends on the temperature. Thus, this effect must be compensated
in the event of changes in temperature (temperature compensation, see below).
2.
Temperature effect of the medium:
The medium pH value is also temperature dependent. For high-precision measurement, the
pH value can be entered in tabular form as a function of the temperature (medium temperature
compensation, see below).
Temperature compensation
• ATC: Automatic temperature compensation: The medium temperature is measured with a
temperature sensor. By means of the temperature input in Mycom S CPM153, this temperature
is used to adapt the slope of the electrode to the medium temperature.
• MTC: Manual temperature compensation: This is useful in processes that run at constant
temperatures. Enter the temperature value manually here to adapt the slope of the electrode to
the medium temperature.
• MTC+Temp.: The pH value is corrected with the temperature manually entered. On the display
however, the value which appears is what the temperature sensor measures in the medium.
Medium temperature compensation
Tables can be created in CPM153 for three different media for medium temperature compensation.
Before starting the process, the most suitable table for the active medium can be selected.
Procedure:
• Take a sample from the process. The pH value should be as close as possible to the set point of
the process.
• In the laboratory, heat the sample to at least the process temperature.
• During the cooling phase, record the value pairs for pH and temperature at the temperatures at
which measurement should later take place (e.g. process temperature and ambient temperature
in the laboratory).
• Enter these recorded value pairs in the table ("Enter value pairs" field). As the reference
temperature ("Enter reference temperature" field), select the temperature at which the set point
of the process is defined (e.g. ambient temperature in the laboratory).
Controller contacts
Options
• Active open (NC contact)
• Active closed (NO contact)
Factory setting
Active closed (NO contact)
Only available if the controller has been
selected as a relay function:
Select the assignment of the controller contacts
as "Active open" or "Active closed".
Limit contacts
Options
• Active open (NC contact)
• Active closed (NO contact)
Factory setting
NO contact
Only available if the limit switch has been
selected as a relay function:
Select the assignment of the limit contacts as
"Active open" or "Active closed".
Fault-signaling contact contact type
Options
• Active on
• Active pulse
Factory setting
Active on
Only for NAMUR function = Off:
Active on:
Contact is active as long as the error
is present.
Active pulse:
Contact is active for 1 second
when the alarm signal occurs.
Chemoclean notice
Chemoclean is always an NO
contact.
Only available if the complete Chemoclean
function (CCC and CCW) is selected in the first
field of the contact configuration:
In the Chemoclean function, the valves of the
CYR10 injector are actuated with an NO
contact.
Function
Options
Info
Содержание Topcal S CPC310
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