Beckhoff KL26 Series. KS26 Series, Документация

Страница: 43 / 47

Commissioning
KL26xx/KS26xx 43 Version: 2.5.0
4.2 Notes on contact-protecting switching of the
EL26x2-0010/ KL26x2-0010 terminals
In order to minimize starting currents in the form of capacitive loads in electronic ballasts, it is possible to
switch on loads at the time when the mains voltage zero crossing occurs. To this end this Bus Terminal
features continuous zero crossing detection for frequencies between 45 Hz and 65 Hz.
At 50 Hz this results in an additional switch on delay to the usual relay delay of 10 ms, at 60 Hz the value is
approx. 8.33 ms.
NOTE
Operation only possible at the same phase
No different phases may be applied at terminal points 2 and 6 (400 V voltage between the terminal points is
not permitted!).
General notes on commissioning
• In order to be able to use this function, an alternating voltage for internal detection must be present
between terminal points 2 and 3. The feeding in of an alternating voltage can be done via the blade
contacts, too.
• Under usual grid conditions the terminal switches near the voltage zero crossing with a typical temporal
accuracy of <1 ms.
• If no zero crossings of an alternating voltage occur for a prolonged period, the system responds directly
to the switch on or switch off request by the PLC, without delay.
• For the EL versions, it is advisable for the PLC to wait until the status becomes “1”, indicating
successful synchronization of the terminal with the zero crossings of the prevailing alternating voltage.
The status bit can be linked via the process data of the terminal and evaluated by the PLC.
• If the “detection” voltage between terminal points 2 and 3 is switched off in the meantime, the Bus
Terminal is only able to maintain the synchronization for a very short time. Thereafter, it indicates the
loss of synchronization by switching off the corresponding status LED or the status bit. A new
synchronization process commences once the supply voltage is restored. Subsequently the switching
operations of the relay once again take place near the voltage zero crossing.
Missing synchronization
If a relay is switched on without synchronization, a current-minimized switch on operation near the
alternating voltage zero crossing cannot be guaranteed.
Mains quality requirements
If mains voltage as “detection” voltage is used: In the event of mains voltage faults, which jeopar-
dize precise synchronization with the mains voltage zero crossing, suitable mains filters should be
used.
Temperature compensation of the terminal
The terminal provides an automatic temperature compensation that allows a soft switching in a wide
temperature range. However temperature alteration can be compensated by the terminal in a deter-
mined dimension only that results by fast alterations to a decreased precision of the zero crossing
detection.