Vaisala K-PATENTS PR-23 AX Series, Instruction Manual

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8 Troubleshooting 69
8.1.4 Message
NO SENSOR
Cause : The current in the cable to this sensor is below 20 mA. Normally this means
that there’s no sensor connected to the cable or that there’s no cable to the DTR. If
this message comes up while a sensor properly is connected, the most likely cause of
this message is a fault in the sensor. It is also possible that the cable is totally dead for
example if it is accidentally cut through.
See also Diagnostic LED LD1/LD3, Section 8.1.2 “Diagnostic LEDs”. The concentration
display will be a dashed line.
8.1.5 Message
NO SIGNAL
Besides the message, the concentration display will be a dashed line although a sensor
is connected.
Cause : The current in the cable to this sensor is in the correct range 20–60 mA, but
no data is coming in from the sensor. This indicates that the Sensor processor card is
faulty.
See also Diagnostic LED LD1/LD3, Section 8.1.2 “Diagnostic LEDs”.
Action : Replace the Sensor processor card.
8.1.6 Message
SHORT-CIRCUIT
The current in the cable to the sensor A/B exceeds 60 mA. First, the DTR attempts
for a short time to reconnect with the sensor in question. If the short-circuit persists,
the sensor in question is switched off completely to protect the Motherboard from
overheating.
See also Diagnostic LED LD2/LD4, Section 8.1.2, “Diagnostic LEDs”.
Note: If two sensors are connected to the DTR, a short-circuit in one of the cables may
disturb the measurement of both sensors as DTR attempts to reconnect. The mea-
surement of the non-affected sensor returns to normal as soon as the short-circuited
sensor is switched off.
If the DTR detects a short-circuit that persists, the affected sensor is switched off to
prevent further damage. The message
SHORT-CIRCUIT
will stay on the screen until the
DTR is powered off and on.
See also Diagnostic LED LD2/LD4, Section 8.1.2, “Diagnostic LEDs”.
Cause and action : The most likely cause of these messages is a problem in the cable
connecting the sensor in question to the DTR. Check that the cable is undamaged and
replace it if necessary, then turn the DTR off and back on.