GE Monitor UPC-900 Operating Instructions Manual page 105

Message
92 WARNING electrode
slope <70 or >110%
94 WARNING<1pH
between cal_buff 1&2
Monitor UPC-900 Operating Instructions 29-0567-16 AB
90 ATTENTION
set<=0mV first
91 WARNING
bad pH ad value
93 pH_cal failed
check electrode
unit
95 Temp cal failed
check cond cell
97 WARNING pH scale
(0-100%)<1pH unit
Action
Only visible to service personnel.
1 Electrode slope is out of range. Check buffers and
recalibrate.
2 Clean the pH electrode and recalibrate.
3 If the message remains, replace the pH electrode.
The difference between the pH of the buffers used
during calibration must be at least 1 pH unit.
1 Check that the conductivity cell is connected. Re-
calibrate.
2 The measured temperature value differs from the
reference value by more than ±5°C, or actual
temperature is lower than –8°C. Recalibrate.
3 If the message remains, replace the conductivity
cell.
The difference between the zero level and full scale
must be at least 1 pH unit. Increase the span between
zero and full scale settings. See Section 5.4 Analog
outputs settings, on page 56.
7 Troubleshooting
7.2 Error messages
105