Multifors 2 - Parallel Bench-top Bioreactor
Interferences
28 March 2018
Page
203
of
211
10.3 Interferences pH-System
Interference
No display or incorrect display of pH
Possible cause
Remedy
By
Sensor cable not connected or not
properly connected.
Connect properly if necessary.
Operator
Measuring system METTLER (ana-
logue)
Function
Temperature compensation
is not activated.
Activate this function in option
Setpoint
of parameter
pH
1
.
Operator
pH drift during long cultivation.
Recalibrate pH with offline values. Refer to the sepa-
rate operating manual of the touch screen software
for details:
(Analogue) measuring system METTLER: chapter
“Recalibrating a METTLER pH Sensor”.
(Digital) measuring system HAMILTON: chapter
“HAMILTON pH Sensor Product Calibration”.
Operator
Faulty pH-sensor.
Test calibration with pH 4 and pH 7 buffer.
Regenerate or replace the sensor.
Consult the documentation of the sensor manufac-
turer!
Operator
1)
This does
not apply
to the measuring system HAMILTON (digital):
this function
MUST
be
deactivated
there!!
Interference
No pH control.
Possible cause
Remedy
By
Parameter
pH
is not activated.
Activate the
parameter.
Operator
Incorrect dead band setting.
Check the dead band (Dead Band in PID settings):
Switch off or enter a small value.
Operator
No addition of reagents (acids and
base).
Check the reagent bottles: Refill if necessary.
Check the hose connections between the reagent
bottles and the culture vessel:
Connect properly if necessary.
Open/remove hose clamps if necessary.
Operator
Pump(s) (base/acid) do/does not op-
erate properly.
Check operation using the rocker switch.
Operator
Pump hose is damaged.
Replace pump head.
Operator
Incorrect hose type connected.
Replace if necessary.
Operator
