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MODEL 1054B C
SECTION 8.0
DIAGNOSTICS AND TROUBLESHOOTING
8.2 TROUBLESHOOTING.
The Model 1054B analyz-
er is designed with the state of the art microprocessor
circuitry. This design incorporates programmed fea-
tures that provide constant monitoring for fault condi-
tions, and the reporting of these faults via Mnemonics
on the instrument display screen. This aids in deter-
mining where to start checking for the cause of failures,
and in some instances, the ability to see changes that
can be used to predict future degeneration of assem-
blies before their complete failure.
8.2.1 Installation Failure.
After completion of installa-
tion the instrument should be checked for operation.
Normally this would consist of Powering up the instru-
ment and checking for:
1.
A self diagnostic fault display. Refer to Table 8-1
for brief description of problem indicated by
mnemonic. Table 8-3 provides a more compre-
hensive problem explanation and actions that may
help solve the problem.
2.
A conductivity reading that is approximately cor-
rect (depending upon sensor installation in either
air or process). Refer to Section 8.2.3 for sensor
checks.
3.
Pressing several of the keypads to determine
whether programming appears to be operational.
Table 8-3 explains problems and actions that may
be helpful in solving them.
4.
Checking output for 4-20 mA output current.
8.2.2 After Operation.
Troubleshooting this instrument
after previous operation should follow normal trou-
bleshooting procedures. Check display. If power is O.K.
the display mnemonic will direct you to the basic area
of malfunction (Sensor, Printed Circuit Boards, calibra-
tion, or temperature compensation).
Use Table 8-1 and Table 8-3 to determine area, possi-
ble problem and actions to take to remedy fault.
Evaluate instrument electronics.
This can be
accomplished by simulating a known conductivity input
and observation of instrument operation. To simulate
sensor operation with known conductivity inputs, use
the following procedures.
1.
Disconnect the Sensor input leads from TB2-1, 3,
6, and 7.
2.
Install decade box or resistor leads to TB2-1 and 3.
(If decade box is not available, simulate desired
conductivity input by either calculating using the for-
mula given in Figure 8-1, or by using the
Conductivity vs. resistance Table in Figure 8-1.)
3.
Install a jumper between TB2-6 and 7. Check
wiring with Figure 8-1.
4.
Power up instrument and enter
SEt
menu.
5.
Turn
Atc
to
oFF
.
6.
Set manual temperature compensation to 25°C
(See Section 4.4 and Figure 4-4).
7.
Set Cell constant to 1.0 (See Section 5.1.1).
8.
Evaluate analyzer response with previous
responses.
Faulty display.
If a faulty display is suspected, enter
the
SET
menu and scroll through to the
dtS
option.
This option will activate all display segments. See
Figure 3-4.
Output Circuit Testing.
To check for problems in the
output circuit, bypass the sensor input and analyzer
calculations by setting a known output current and
checking item driven by output current and checking
the operation of valves, pumps, recorders, etc. For
directions on how to set output current, refer to
Section 4.9.
8.2.3 Sensor Troubleshooting.
In addition to the sen-
sor fault mnemonics, the analyzer can display informa-
tion pertinent to determining if sensor has become
coated, or if there is a conductivity versus temperature
problem, or an application problem.
Sensor Coated.
As the cell becomes coated, or affect-
ed by the process, the cell factor will change. Tracking
this change in cell factor will prevent use of a sensor
that has lost its sensitivity because of contamination or
damage.
CAUTION
Standardizing the instrument results in the
cell factor being returned to 1.0.
This instrument tracks the change in calculated cell
factor from the initial cell factor value of 1.0 every time
the unit is standardized. The cell factor should be
checked and tracked to set up a regular maintenance
schedule and can be seen in the following manner:
1.
Press
ACCESS
key twice.
2.
SEt
will be displayed briefly followed by
Cin
.
3.
SCROLL
(
é
) to display
Fct
and press
SELECT
.
4.
To return to normal operation, press
PV
.
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