5.2.1 Logic Section
Microprocessor
The control card contains most of the logic section (see
). The primary logic element of the control
card is a microprocessor, which supervises and controls all
functions of operation of the drive. In addition, separate
PROMs contain the parameters to provide programmable
options. These parameters are programmed to enable the
drive to meet specific application requirements. This data is
then stored in an EEPROM which provides security during
power-down and allows for changing the operational
characteristics of the drive.
PWM waveforms
A custom-integrated circuit generates a pulse width
modulation (PWM) waveform which is then sent to the
interface circuitry on the power card.
M
icr
opr
oc
essor
Data
RAM
PROM
EEPROM
VVC
+
Control
Power
Local
Control
Panel
Analog
inputs
Digital
inputs
Analog
outputs
Digital
channel
D
A
A
D
Power
feedback
2
1
1
1
Relay
130BX134.11
Illustration 5.2 Logic Section
The PWM waveform is created using an improved control
scheme called VVC
+
, a further development of the earlier
VVC (voltage vector control) system. VVC
+
provides a
variable frequency and voltage to the motor which
matches the requirements of the motor.
Local control panel (LCP)
Another part of the logic section is the local control panel
(LCP). The LCP is a removable keypad/display mounted on
the front of the drive. The LCP provides the interface
between the internal digital logic and the operator.
All the programmable parameter settings can be uploaded
into the EEPROM of the LCP. This function is useful for
maintaining a back-up drive profile and parameter set. It
can also be used, through its download function, in
programming other drives or to restore a program to a
repaired unit. The LCP is removable during operation to
prevent undesired program changes. With the addition of a
remote mounting kit, the LCP can be mounted in a remote
location of up to 3 m (10 ft) away.
Control terminals
Control terminals, with programmable functions, are
provided for input commands such as run, stop, forward,
reverse, and speed reference. Extra output terminals are
provided to supply signals to run peripheral devices or for
monitoring and reporting status.
The control card logic can communicate via serial link with
outside devices such as personal computers or
programmable logic controllers (PLC).
The control card also provides 2 voltage supplies for use
from the control terminals. The 24 V DC is used for
switching functions such as start, stop, and forward/
reverse. The 24 V DC supply can supply 200 mA of power,
part of which can be used to power external encoders or
other devices. A 10 V DC supply on terminal 50 is rated at
17 mA is also available for use with speed reference
circuitry.
The analog and digital output signals are powered through
an internal drive supply.
Two relays for monitoring the status of the drive are on
the power card. They are programmable through
parameter group 5-4* Relays
. The relays have different
ratings. See the corresponding
operating guide
or
design
guide
for more information on ratings.
The control card logic circuitry allows for the addition of
option modules for synchronizing the following types of
software:
•
Control
•
Serial communications
•
Extra relays
•
Cascade pump controller
•
Custom operating
5.2.2 Logic-to-power Interface
The logic-to-power interface isolates the high voltage
components of the power section from the low voltage
signals of the logic section. The interface section consists
of the power card and gate drive card.
Control card
The control card handles much of the fault processing for
output short circuit and ground fault conditions. The
power card provides conditioning of these signals. The
control card also handles scaling of current and voltage
feedback.
Power card
The power card contains a switch mode power supply
(SMPS), which provides the unit with 24 V DC, (+) 18 V DC,
(–) 18 V DC, and 5 V DC operating voltage. The SMPS
Internal Drive Operation
VLT
®
FC Series, D1h–D8h, Da2/Db2/Da4/Db4, E1h–E4h, J8/J9
44
Danfoss A/S © 02/2019 All rights reserved.
MG94A502
5
5
Содержание VLT FC Series
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