K-Patents PR-21-S - Manual (Page 80)

74 PR-21-S instruction manual
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 concen-
tration 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. To replace, follow instructions in Sec-
tion 7.3.1. Observe the note at the end of Section 7.3.2, “Removing electronic cards
PR-10301 and PR-10201”.
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 per-
sists, 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
measurement 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 un-
damaged and replace it if necessary, then turn the DTR off and back on.