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4.3.10 Setting Warning Threshold
A warning is triggered if the UV-C output decreases to such an extent that the sensor signal
drops below the warning threshold. The lamp protection tubes should be cleaned or the lamps
replaced or the water quality improved by suitable preparation in order to avoid the signal
dropping below the safety threshold. The signal dropping below the warning threshold is
indicated by a flashing arrow on the display.
A signalling device can be connected to the WARNING THRESHOLD signalling relay of the
control. The relay is closed when the warning threshold is undershot.
WARNING!
After changing a UV lamp, check the safety and warning threshold and readjust if
necessary!
IMPORTANT!
The warning threshold must be above the safety threshold.
It is not possible to set the warning threshold below the safety threshold.
Observe the supplementary instructions for special applications, in which the sensor signal
is displayed in %!
Preconditions:
• The stable UV-C intensity of the UV lamps was noted down
• The safety threshold was set (see Section 4.3.9 “Setting Safety Threshold”).
➤
Set the warning threshold to 110 % of the set safety threshold.
Example: Set safety threshold: 50 W/m
2
Therefore: Warning threshold = 50 W/m
2
1.10 = 55.0 W/m
2
The procedure for setting the safety threshold and warning threshold is now completed, the
system is ready for operation and can be switched on with the Start/Stop key.
4.3.11 Analogue Output Sensor Signal Assigning Standard Signal
The signal from the UV-C sensor can be recorded on a plotter for documentation purposes.
The plotter is to be connected to the standard output of the control for this purpose.
It is possible to choose between a standard signal of 0 to 20 mA and 4 to 20 mA:
• 0 or 4 mA corresponds to the sensor signal 0 W/m
2
• 20 mA can be assigned to any value.
IMPORTANT!
The sensor signal value assigned to 20 mA simultaneously serves as the maximum value of
the trend display.
Set this sensor signal value to 125 % of the maximum value to ensure the trend display
(see 4.3.1) can never “overflow”.
Presetting
0 W/m
2
= 0 mA
400 W/m
2
= 20 mA (depending on settings)
55.0 W/m
2
Warning threshold
Control
Analogue output
0 W/m
2
= 0 mA
400 W/m
2
= 20 mA
