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Device and function description
Only at variant /_ _ 1
Digital selection via the software Inputs: SW1 to SW4
Four various frequency modes with different response parameters, can be
configured via the software Inputs: SW1 to SW4 (see Table). The electric
power supply for the inputs should be between 10V DC and 26.4V DC
to GND. A switchover configuration can also be undertaken during the
operating mode. If the frequency mode is changed during operation, the
switching time (t
) for the frequency evaluation and the switching tolerance
U
(n
) for the rotary motion evaluation runs under the condition that the output
U
relays are switched through and the start-up suppression (t
During the switching time resp. switching tolerance there is no evaluation
of frequency resp. rotary motion, and the output relays remain energized.
If the frequency mode is changed again during the switching time resp.
the switching tolerance, the switching time resp. switching tolerance is not
restarted. Upon expiry of the switching time resp. switching tolerance, the
monitoring is continued with the currently set frequency mode. By means
of the switching time resp. switching tolerance it is possible to suppress an
alarm message during the start-up or braking phase of a generator or motor.
SW1
SW2
SW3
0
0
1
0
1
1
1
0
0
1
1
0
Caution !
Permanent switching of the frequency modes (immediately
!
upon expiry of the switching time resp. switching tolerance)
may result in the device acting like with the muting function,
i.e. the frequency monitoring resp. rotary motion monitoring
is bridged and the output relays are permanently switched
through.
Muting function
The frequency monitoring function or direction of rotation monitoring can be
overridden on the display and by an appropriate activation of the software
Digital Inputs: SW1 to SW4. For this purpose, the muting function should be
activated when parametering on the display. Once this function is activated,
then it will continue to be possible to continue to switch over between the
frequency moduses: 1 to 3, as described above. Should a selection be made
of the frequency mode 4 (muting) via the 'SW' software inputs, then no further
frequency monitoring or direction of rotation monitoring will be conducted.
The output relays remain permanently on and the start-up delay function
(t
), the switchover time period function (t
A
the alarm-delay function (t
), Start-up tolerance (n
V
(n
), and Alarm tolerance (n
) will all be reset.
U
V
) has expired.
A
SW4
Mode
1
Frequency mode 1
0
Frequency mode 2
1
Frequency mode 3
0
Frequency mode 4
), the reset-delay function (t
U
), Switch-over tolerance
A
Device and function description
Analogue output A+ and A GND
The analogue output 2-10 V shows the actual measured frequency. The
maximum value of the analogue output (10 V) is equal to the adjusted
upper frequency threshold. The minimum value of the analogue output
(2 V) is equal to the adjusted lower frequency threshold. The scaling is
frequency linear.
In the monitoring function „underfrequency" the maximum value of the
analogue output is equal to the highest possible setting value of the device
(Variant UH 6937/0_ _ = 600 Hz and UH 6937/1_ _ = 1000 Hz).
In the monitoring function „overfrequency" the minimum value of the
analogue output is equal to 0 Hz.
If the muting function or the frequency monitoring and the direction of rotation
monitoring are deactivated is selected, the maximum value of the analogue
output is equal to the maximum setting value of the device (Variant UH 6937/0_ _
= 600 Hz and UH 6937/1_ _ = 1000 Hz) and the minimum value is equal
to 0 Hz.
In the case of a failure the analogue output goes to 0V.
The analogue output is not safety related. It can be used for diagnosis.
Switchover time period t
The switchover time period expires when the frequency mode is altered
during operations at the digital inputs: SW1 to SW4, the output contacts
are closed, no start-up delay function is running and the Switchover Time
Period: 'tU' has not already been initiated and/or is running. During this time
period, no frequency monitoring is conducted and the output contacts remain
on (depending on the evaluation of the direction of rotation).
Switch-over tolerance n
The switch-over tolerance runs out if the frequency modes are changed
using the digital inputs SW1-SW4 during operation, the output contacts are
closed, no start-up tolerance is running and nU has not already been started
or is running out. During this time, no evaluation of the direction of rotation
takes place and the output contacts are switched through (depending on
the frequency evaluation).
),
F
25
U
U
UH 6937 / 30.05.22 en / 551A
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