Endress+Hauser Liquisys M CCM223, Operating Instructions Manual

Page: 90 / 124

Maintenance Liquisys M CCM223/253
90 Hauser
8.2.3 pH/ORP measurement
Simulation takes place with a pH/mV simulator or an mV voltage source.
On the CCM223/253, pH or mV must always be measured symmetrically. For this
reason, each simulation requires potential matching with the simulator. Connect the
reference signal of the simulators (normal screen of the pH coaxial measuring line) to
the PA/PM terminal of the transmitter.
Zero point rapid test
• On the CCM223 connect the BNC inner conductor to the BNC receptacle and the PM
terminal.
• On the CCM253 connect the pH terminal, the Ref terminal and the PM terminal.
• For pH, the reading must be about 7, for ORP about 0 mV.
Test with DC voltage source
8.2.4 Flow monitoring
Flow is monitored by an inductive proximity switch (INS) in the CCA250 assembly. This
switch is powered by 15 V from the auxiliary voltage output of the transmitter.
Function of the INS
Test or emergency mode
If you connect terminal 93 to terminal 85 and terminal 94 to terminal 86, this simulates an
active proximity switch and thus a correct flow.
Do not run the measuring system continuously in this state and switch the flow monitor
back on as soon as possible!
pH value Simulation
2 295 mV
4 177 mV
7 0 mV
9 -118 mV
12 -295 mV
Flow INS INS output
yes damped low impedance
no not damped high impedance