Hach-Lange SIGMA SD900 Refrigerated Sampler and All Weather Refrigerated Sampler User Manual - Manual (Page 93)

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Troubleshooting
2. Press each key on the keypad (except the BACK key). The
display should show the name of the key that was pressed.
3. To exit the test, press BACK key.
7.3.3 LCD diagnostic
Use the LCD diagnostic to make sure the controller display is
operating correctly.
Procedure:
1. Select DIAGNOSTICS > LCD DIAG from the main menu to begin
the test.
2. Observe the display. Each row will show SD900 and then each
pixel will darken. When complete, the display will briefly show
“test complete”.
7.3.4 Liquid sensor diagnostic
Use the liquid sensor diagnostic to show the current calibration
information for the liquid sensor.
Procedure:
1. Select DIAGNOSTICS > LIQ SENSE DIAG from the main menu.
2. The display will show the input frequency (MHz), the output
voltage (VDC) and the signal to noise ratio for the current
calibration.
7.3.5 Thermal diagnostic (AWRS only)
Use the thermal diagnostic to show the thermal control unit
parameters: cabinet temperature, evaporator heater temperature,
thermal setpoint and calibration offset.
Procedure:
1. Select DIAGNOSTICS > THERMAL DIAG from the main menu.
2. The display will show the thermal control parameters. Use the
UP and DOWN arrow keys to view more parameters.
Note: Thermal diagnostics screen cannot be viewed when the All Weather
unit is running in Inhibit mode, i.e. when the AWRS Inhibit has been
enabled in set-point sampling menu.
7.3.6 SDI-12 diagnostic
The SDI-12 diagnostic can be used to obtain information about the
communication between the SDI-12 device and the SD900.
From the MAIN MENU select DIAGNOSTICS> SDI-12.
If no SDI-12 device is connected or the device is not
communicating with the SD900, the display shows this information.