Manual Power Quality Filter PQFM
Electrical design and installation 85
In order to obtain full redundancy with filters consisting of more than one master unit,
the digital inputs of all the units in a multi-master arrangement have to be set up and
cabled in the same way and the individual PQF-Managers have to be set up accordingly.
Once the cabling has been finished, the power to the filter may be restored. Refer to
Section 7.9.1.4
for guidelines on how to set up the digital inputs according to the
function required.
6.12.6 Implementation of local start/stop buttons
WARNING: If a function is assigned to a digital input, the same function must never be
assigned to the other digital input. Otherwise the filter may behave erratically.
The PQFM active filter is equipped with a start/stop function integrated in the PQF-
Manager user interface. If the customer desires this however, he can add extra
start/stop buttons (not provided) to the filter system. The start and stop button has to
be connected to the PQF-Manager’s digital inputs and the PQF-Manager has to be set
up accordingly.
Note that in a multi-unit filter system in which more than one master system is present,
the digital inputs of all masters have to be set up and cabled in the same way to obtain
full redundancy.
Two connection approaches exist:
−
The first approach is to use one digital input for the start function and the second
digital input for the stop function.
shows the PQF-Manager setup for the
input considered and the resulting effect when applying voltage to this input.
Table 34: Filter behavior as a function of the PQF-Manager settings for local start/stop and
using 2 digital inputs
PQF-Manager setup for
digital input
Vlow applied to digital
input
Vhigh applied to digital input
Edge ON
No effect
Filter starts on rising edge
Edge OFF
No effect
Filter stops on rising edge
Remark: Vlow = 0 Vdc, Vhigh = 15-24 Vdc
When using the Edge ON function the filter can only be switched on by applying voltage
to the digital input considered. It is therefore recommended in that case to configure
and cable the second digital input as Edge OFF. Refer to
Section7.9.1.4
for guidelines on
how to set up the digital inputs according to the function required.
The electrical requirements of the digital inputs are as discussed in
Section 4.5.