WPI STX2-PLUS, Instruction Manual

Page: 12 / 16

8 World Precision Instruments
TROUBLESHOOTING
Issue Possible Cause Solution
Electrode
tips
over when released
The cable is heavy and can cause
the electrode to tip over if too much
cable is in the air.
Lay the cable on the tabletop as close to the
electrode head as possible.
The reading appears to be drifting* (see the drift
definition below).
The electrodes are coated. The Electrodes requires enzymatic cleaning.
The fluid temperature in the plate is
changing.
Use a plate warmer.
In a 5% CO
2
environment, a loss of
CO
2
causes the media pH to change,
and the resistance reading may
increase sharply.
A 5% CO
2
environment can help in reducing pH
media changes. A plate warmer can reduce out
gassing.
The electrode reading is unstable. (see the stabil
-
ity definition below).
The electrodes are coated. The electrodes require enzymatic cleaning.
The electrodes need to be chlorided. The electrodes require chloriding
Radio frequency interference Turn off or move any cellular phones farther
away from the experimental setup.
NOTE : If you have a problem/issue with that falls outside the definitions of this
troubleshooting section, contact the WPI Technical Support team at 941.371.1003 or
technicalsupport@wpiinc.com.
* Defining Term:
• Drift–Readings that continuously increase or decreases a significant value (either
voltage or resistance) over time. Example 1: At 10 mV the Pd reading is increasing
1 mV/minute. (A drift of 0.1 mV/minute is acceptable.) Example 2: At 1000 Ω
the reading is increasing 100 Ω/minute. (A drift of 10 Ω/minute is acceptable.)
Excessive drift may be caused by a coated electrode, pH or temperature changes.
See “Cleaning/Maintaining the STX2-PLUS Electrodes” on page 5.
• Instability–At 500 Ω, the reading jumps from 450 to 550 Ω and will not settle down
(an instability ±5 Ω is acceptable in the 500 Ω range. In the higher ranges, up to
±1000 Ω is acceptable at the 100K range. Electrodes showing instability may be
coated with DMEM and require enzymatic cleaning. See “Cleaning/Maintaining the
STX2-PLUS Electrodes” on page 5.