Mycom S CPM 153
8 Troubleshooting
Hauser
99
8.1.2
Process-specific errors
Error
Possible cause
Remedial action
Equipment needed,
spare parts
Instrument
unconfigurable,
Display for code prompt
is 9999
Instrument hardware is locked via
keyboard (Keys "CAL" + "DIAG"
simultaneously = security locking)
Press "MEAS" and "PARAM" simultane-
ously to unlock.
Measuring chain zero
point not settable
Reference system poisoned
Test with new electrode
pH/mV electrode
Membrane blocked
Clean or grind diaphragm
HCl 3%, file (only file in one direction)
Measuring line broken
pH input on instrument
short-circuit
⇒
Display pH7
pH input on instrument
short-circuit
⇒
Display pH7
Unsymmetrical sensor voltage too
high
HCl 3%, file (only file in one direction)
Clean membranes or test with
different electrode
Potential matching (PA/PM) Mycom
⇔
Incorrect medium
unsymm.: no PM or PM on PE
symm.: PM connection needed
Connection see Chap. 4
Keine Kalibrierung
möglich, weil Sensor-
Anpasszeit zu lang.
Bei IsFET-Sensor: Feuchtigkeitsfilm
der Messfläche abgerissen durch
Abtrocknen oder Ausblasen mit
Druckluft.
Feuchtigkeitsfil sicherstellen oder Puf-
fer-Verweildauer > 6 Min. sicherstellen.
IsFET-Sensor nicht mit Druckluft reini-
gen.
No or slow
display change
Electrode soiled
Clean electrode
see Chap. 7.1.3
Electrode aged
Replace electrode
New electrode
Electrode defective (reference lead)
Replace electrode
New electrode
Inner buffer missing
Check KCl supply (0.8 bar above
medium pressure).
KCl (CPY 4-x)
Problem with diaphragma or
missing electrolyte
Measuring chain slope
not adjustable/slope too
small
Connection not at high impedance
(humidity, dirt)
Test cable, connector and junction
boxes
pH simulator, see also Chap. 7.1.2
Instrument input defective
Directly test instrument
pH simulator
Electrode aged
Replace electrode
pH electrode
Measuring chain slope
not adjustable
Hairline crack in glass membrane
Replace electrode
pH electrode
Connection not at high impedance
(humidity, dirt)
Test cable, connector and junction
boxes
pH simulator, see also Chap. 7.3.2
Semi-conductor layer in measuring
cable not removed
Check inner coaxial cable, remove
black layer
Permanent, incorrect
measured value
Electrode not immersed or protec-
tive cap not removed
Check installation position, remove
protective cap
Air cushion in assembly
Check assembly and installation posi-
tion
Earth fault at or in the instrument
Test measurement in insulated vessel,
possibly with buffer solution
Plastic vessel, buffer solutions Beha-
viour, when instrument is connected
to process?
Hairline crack in the glass memb-
rane
Replace electrode
pH electrode
Instrument in impermissible opera-
ting state (no response on pressing
key)
Switch instrument off and on
EMC problem: If repeated, check
grounding and wire routing
Incorrect temperature
reading
Incorrect sensor connection
Check connections using wiring dia-
gram
Wiring diagram see Chap. 4.1.1
Measuring cable defective
Check cable
Ohmmeter
Incorrect sensor type selected
Set sensor type on instrument
(Field 141)
Check temperature sensor with
Ohmmeter.
Sensor defective
Check sensor