Endress+Hauser Liquisys M CCM223, Operating Instructions Manual

Page: 51 / 124

Liquisys M CCM223/253 Commissioning
Hauser 51
6.4.6 Check
Check
The CHECK function group is only available for devices with a Plus Package (versions ES and
EP).
In the CHECK function group, you can select different monitoring functions for the
measurement.
By default all monitoring functions are off. The Sensor Check System is adapted to the
current application conditions by adding and setting suitable functions.
Alarm threshold monitoring
When you perform a chlorine or chlorine dioxide measurement without chemical
entrainment control, sensor errors lead to a measured value error, but have no impact on the
process medium (examples: monitoring measurement in water-works). Sensor errors
normally cause high or low readings that are implausible. This is detected and signalled by
user-definable alarm thresholds.
Controller monitoring
When you perform chlorine or chlorine dioxide measurements with simultaneous chemical
entrainment control, sensor errors do not result in incorrect measured values but have direct
impact on the state of the process medium.
In particular in case of controlled water disinfection, there is a process-related risk that
chemical dosing is not switched on due to a permanently high measured value. This causes
considerable danger to process stability, or even a serious health hazard for humans. On the
other hand a measured value that is permanently too low leads to uninterrupted chemical
dosing and thus to higher operating costs and a risk of corrosion.
These cases are detected and signalled thanks to user-definable monitoring times for
maximum permitted controller switch-on and switch-off times.
Sensor activity monitoring
Impacts of the process medium on the sensor can also result in incorrect measured values.
For example, a strong deposit on the sensor membrane can lead to a highly sluggish or even
a constant measuring signal. This is detected and signalled by continuously monitoring the
signal.
F8
Automatic cleaning
function start no
yes
This field is not available for certain errors,
see "Trouble-shooting and fault
elimination" section.
F9
Select return to
menu or next error
next = next error

R
If  R is selected, you return to F, if next is
selected, you go to F5.
Coding Field Setting range
(Factory settings, bold) Display Info
F8
CleanTrig
no
F9
Select
next