80 Electrical design and installation
Manual Power Quality Filter PQFM
−
The external 24 V power supply fails OR
−
Both filter units are disconnected from the supply.
6.12.2.2 Digital outputs
A second method to implement the alarm functionality is to use the PQF-Manager’s
programmable digital output contacts. Use this approach when the condition for alarm
is uniquely defined, e.g. an alarm has to be given only when the filter trips due to an
unacceptably high network voltage or when the filter trips due to a well-defined internal
error. This type of alarm has to be cabled on the 8 pin terminal block situated at the top
right corner when looking at the PQF-Manager from the rear (Cf.
).
The digital output contacts have a common point (cabled on contacts 1 and 2) and are
of the NO-type (normally open). The contact ratings are:
−
Maximum continuous ac rating: 440 Vac/1.5 A.
−
Maximum continuous dc rating: 110 Vdc/0.3A.
−
The common is rated at 9 A/terminal, giving a total of 18 A.
−
When using a power supply of 24Vdc, a minimum current of 10 mA should be
drawn by the circuit connected to the digital output contact.
shows the status of a digital output contact configured as alarm contact for
different operation modes of the filter.
Table 29: Status of a digital output contact configured as alarm contact for different
filter operation modes
Filter state
Normally open digital contact state
Disconnected from the supply
Open
Filter (auxiliaries) connected to
the supply, no error present
Open
Filter (auxiliaries) connected to
the supply, predefined error
appears
Closes when error present for 3 minutes.
Otherwise, contact remains open.
Filter (auxiliaries) connected to
the supply, predefined error
disappears
When closed before, opens when error disappears.
When opened before, remains open.
The alarm conditions that can be assigned to a digital output are given in
.
The
assignment must be made with the PQF-Manager. Any of the six digital outputs can be
used to cable an alarm. A maximum of 3 alarms can be assigned to the digital outputs.
Note however that by default the digital outputs have been set up for monitoring other
functions than alarms (cf.
) Refer to
Section 7.9.1.4
for guidelines on how to
navigate to the digital output setup menu.
