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3.5 Operating hours & Constant light output (CLO)
Luminous flux of LEDs reduces over time as the diodes age, Constant Light Output (CLO) function is utilized to continuously
compensate for the drop in luminous flux of the luminaire. This compensation is automatic, requiring no maintenance resource
and the installation does not need to be over installed to compensate for future light depreciation from the diodes. You also can
receive data of how long the luminaire has been operating to organize a replacement before the end of LEDs' service life.
3.5.1 Operating hours
Operating hours can be used to monitor service time of the lumiaire and used to prepare a replacement before the lamp is
over its lifetime so as to maintain a constant level of illumination for the building.
The chart shows the dynamic range for thisparameter:
ETS- text Dynamic range
[default value ]
Comment
Counting of operating hours
in
Hours
Seconds
Choose what unit is used in records
Send counters on
change(per hour)
not active
active
Sends out the operating time every hour when active
Send counters cyclically 10min, 20min, 30min, 40min, 50min,
60min, not active
[not active]
Sends out the operating time at intervals you desire
Constant light output(CLO) not active
active
Activates the CLO function
The following chart shows the objects for this parameter:
Number Name Length Usage
23
Operating hours(Counter, in
seconds/ hours)
4bytes Sends the operating time of the driver count to theed
system at regular intervals when active. Unit: seconds
or hours
24
Operating hours(set value, in
seconds/hours)
4 bytes Overwrites the operating time the driver counted. Used
to reset the timer when replacing new LEDs. Unit:
seconds or hours
3.5.2 Constant light output (CLO)
Lumen depreciation is the luminous flux lost over time and it is irreversible. Generally, luminous flux of lamps without CLO
decreases to 80% from 100% after 50,000 hours. In contrast to lamps with CLO, albeit beluminous flux stars at 80%, it can
still mantained at around 80% even the lamps have been servicing for the same period of 50,000 hours. The method of
CLO is that the lumiaire starts its service life at a lower operational current and the current gradually increases over its
service life to compensate for the LED's light depreciation.
NOTE:
The PWM-KN saves the up-to-date operating time information into its MCU flash memory every 10 mins. If there is bus
voltage failure that occurs, the driver will lose the up to date operating time. In case the bus voltage is back to normal, the
operating time data is fetched from its flash memory.
For example 1, The PWM is already operating for 300 minutes. After 9 minutes, the bus voltage is lost and back to normal,
For example 2, The PWM is already operating for 300 minutes. After 11 minutes, the bus voltage is lost and back to normal,
the operating time acquired from the PWM internal flash is then 300 minutes.
the operating time acquired from the PWM internal flash is then 310 minutes.
Counting of operating hours & CLO not active active
Counting of operating hours in
Send counters on change (per hour)
Constant light output (CLO)
Send counters cyclically
hours seconds
not active active
not active active
not active