Yokogawa EXA ISC202 2-wire Conductivity Transmitter/Analyzer - Manual (Page 66)

IM 12D06A03-01E
Trouble shooting 8-1
8. TROUBLESHOOTING
8-1. Introduction
The EXA ISC202 microprocessor based conductivity analyser continuously monitors the condition of
all key components of the measuring system to ensure that measurement is dependable. If a fault is
detected this is immediatly signalled. Errors are shown on the display with a code. Table shows the
errors which can be detected and gives information to help locate the fault or identify the error. Faults
detected while the instrument is on line can also be signalled by a burnout (section 5-5).
8-2. Self diagnostics of the conductivity sensor
During measurement the instrument adjusts the measuring parameters to give the best conditions for
the actual value being measured. At all values the instrument checks the signal from the cell to search
for distortion. If there is a problem with the installation of the cell and this becomes defective this will
trigger an error message on the display possibly accompanied by a by a burnout signal (section 5-5).
8-3. Self diagnostics of the temperature sensor
The temperature sensor, which is normally built into the conductivity cell, is checked to detect damage
or faulty connections.
8-4. Self diagnostics of the electronics
The microprosessor opertion is checked by a watchdog which initiates an electronic reset if the normal
functions suffers severe interference. During reset the instrument checks the program and all stored
data.
If a fault is then detected an alarm is given.
8-5. Checking during operation
Whenever the instrument is being programmed or calibrated, data is checked and an error is shown
when appropriate. Should this occur the new data is rejected and the instrument continues to work with
the previuos settings.