VLT
®
4000 VT
■
Analog inputs
Two analog inputs for voltage signals (terminals 53 and
54) are provided for reference and feedback signals.
Furthermore, an analog input is available for a current
signal (terminal 60). A thermistor can be connected
to voltage input 53 or 54. The two analog voltage
inputs can be scaled in the range of 0-10 V DC; the
current input in the range of 0-20 mA.
The table below gives the possibilities for
programming the analoge inputs.
Parameter 317
Time out
and 318
Function after
time out
allow activation of a time-out function on all
analoge inputs. If the signal value of the reference
or feedback signal connected to one of the analoge
in-put terminals drops to below 50% of the minimum
scaling, a function will be activated after the time out
determined in parameter 318,
Function after time out
.
Analog inputs
terminal no.
53(voltage)
54(voltage)
60(current)
parameter
308
311
314
Value:
No operation
(NO OPERATION)
[0]
[0]
✭
[0]
Reference
(REFERENCE)
[1]
✭
[1]
[1]
✭
Feedback
(FEEDBACK)
[2]
[2]
[2]
Thermistor
(THERMISTOR)
[3]
[3]
308 Terminal 53, analog input voltage
(AI [V] 53 FUNCT.)
Function:
This parameter is used to select the required
function to be linked to terminal 53.
Description of choice:
No operation
Is selected if the AFD is not to react
to signals connected to the terminal.
Reference
Is selected to enable change of reference
by means of an analog reference signal. If reference
signals are connected to several inputs, these
reference signals must be added up.
Feedback
If a feedback signal in connected,
there is a choice of a voltage input (terminal 53 or
54) or a current input (terminal 60) as feedback.
In the case of zone regulation, feedback signals
must be selected as voltage inputs (terminals 53
and 54). See
Feedback handling
.
Thermistor
Is selected if a thermistor integrated in the
motor is to be able to stop the AFD in case of motor
overtemperature. The cut-out value is 3 kohm. If a
motor features a thermal switch instead, this can also
be connected to the input. If motors run in parallel,
the thermistors/thermal switches can be connected
in series (total resistance < 3 kohm). Parameter 117
Motor thermal protection
must be programmed for
Thermal warning
[1] or
Thermistor trip
[2], and the
thermistor must be inserted between terminal 53 or 54
(analoge voltage input) and termi-nal 50 (+10 V supply).
A motor thermistor connected to terminals 53/54
must be double isolated to obtain PELV.
MG.40.A7.22 - VLT is a registered Danfoss trademark
86