ABB AW400 Series, Instruction Manual

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8 MAINTENANCE
AW400 housing can be externally cleaned with a cloth slightly wetted with alcohol and water, paying attention
not to damage the keyboard.
8.1 Periodical operations
All Monitors need cleaning of the sensors at periodical intervals, this depends on type of sensor and process
characteristics. For further details refer to the specific sensor Instruction Manual. The Monitors also need
periodical check of sensitivity and calibration if required.
8.1.1 Automatic sensitivity check during dual point calibration
During dual point calibration, and if no one of the two points is bypassed, AW400 performs an automatic
sensor sensitivity check. If the sensitivity is too low the display will show the message Bad In. Refer to the I.B.
pertinent to each specific sensor for details on how to fix the problem. If the message Fault appears the signal
generated by the sensor is abnormally high. Refer to the I.B. pertinent to each specific sensor for details on
how to fix the problem.
8.1.2 Sensor signal check
The signal generated by the sensor and by the temperature sensing element can be directly read (in µA or
mV and in Ω) on AW400 display simply by entering the Analog I/O, input signals submenu, under Instrument
Test submenu. This is a very easy way to define if the sensor is correctly working just verifying its signal and
comparing it to a lab analysis of the measured value. See the pertinent I.B. for nominal signal to be expected
from each type of sensor.
CAUTION!
Do not use acids, chemicals solvents and organic substances for AW400 cleaning.