FIS HDL1, Operating Manual

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TROUBLESHOOTING
AUDIT LOG
This is useful for viewing a history of changes to the data logger parameters. Things
such as new programs being loaded, time being changed, and memory being
cleared are all recorded in the audit log. If the data logger is called by several
different persons or organizations, the audit log can indicate if you need to activate
password protection as the log will indicate if unwanted changes are being made to
your system (although it cannot tell you who made the changes).
SENSORS
For SDI sensors, there are several possible areas of difficulty.
If you are installing a new system or are adding sensors to an existing system there
are several items that can cause trouble:
Each sensor MUST have a unique address ( -- if two sensors have the
same address then they try to communicate simultaneously, corrupting
the reply). Note that many sensor manufacturers ship all sensors set to
an address of 0 and expect the user to change it to match his system.
The data logger program must have the right command and field set up
in order to read the sensor properly. This is particularly important with
some sensors that change the field number when you set it up
differently from its previous setting. For example, you have a sensor
that is programmed to return pH, DO and conductivity, and another
identical unit that you have programmed for just pH and conductivity,
the conductivity value in the second unit may be in a different field than
the first unit (the second field instead of the third field). This varies from
manufacturer to manufacturer.
Power and signal distribution problems. If you are using FTS supplied
units with the connectors in place, then this is not an issue. However, if
you need to use junction blocks, or are using sensors with bare wire
ends, be very careful when wiring these systems, as there is little
consistency in color codes from manufacturer to manufacturer. FTS
uses the red wire for +12 Vdc, the black wire for ground, and white for
the signal wire, as this matches most common North American
conventions. It is also important to control moisture when using junction
blocks. There will always be 12 Vdc on one of the wires at all times, so
if there is high humidity in the box containing the junction block,
electrolytic corrosion will occur very rapidly, destroying the wires and
junction block. While this is occurring, there may be intermittent failures
and the sensor may seem to be unreliable.
CHANGING AN EXISTING SETUP
If replacing a sensor, make sure that its address is the same as the one
it replaces.
If reconfiguring a sensor to return different parameters, make sure that
the program field number is correct for the reconfigured sensor
If using junction blocks for power or signal distribution, check them
carefully for corrosion or moisture problems. Only one needs to be bad
to prevent the entire SDI system from working properly, since the power
and data signals are common to every sensor.