Mechanical Brake Control; Serial Communication - Danfoss VLT AutomationDrive Operating Instructions Manual

Installation

2.4.5.9 Mechanical Brake Control

In hoisting/lowering applications, it is necessary to be able
to control an electro-mechanical brake:
•
Control the brake using any relay output or digital
output (terminal 27 or 29).
2 2
•
Keep the output closed (voltage-free) as long as
the frequency converter is unable to 'support' the
motor, for example due to the load being too
heavy.
•
Select Mechanical brake control [32] in par. 5-4* for
applications with an electro-mechanical brake.
•
The brake is released when the motor current
exceeds the preset value in 2-20 Release Brake
Current.
•
The brake is engaged when the output frequency is
less than the frequency set in 2-21 Activate Brake
Speed [RPM]or 2-22 Activate Brake Speed [Hz], and
only if the frequency converter carries out a stop
command.
If the frequency converter is in alarm mode or in an over-
voltage situation, the mechanical brake immediately cuts in.
In the vertical movement, the key point is that the load must
be held, stopped, controlled (raised, lowered) in a perfectly
safe mode during the entire operation. Because the
frequency converter is not a safety device, the crane/lift
designer (OEM) must decide on the type and number of
safety devices (e.g. speed switch, emergency brakes etc.) to
be used, in order to be able to stop the load in case of
emergency or malfunction of the system, according to
relevant national crane/lift regulations.
Illustration 2.17 Connecting the Mechanical Brake to the
Frequency Converter
20
®
VLT AutomationDrive Operating
Instructions

2.4.6 Serial Communication

Connect RS-485 serial communication wiring to terminals
(+)68 and (-)69.
•
•
Illustration 2.18 Serial Communication Wiring Diagram
For basic serial communication set-up, select the following
1.
2.
3.
•
•
•
•
®
MG.33.AJ.02 - VLT is a registered Danfoss trademark
Screened serial communication cable is
recommended
See 2.4.2 Earth (Grounding) Requirements for proper
grounding
Protocol type in 8-30 Protocol.
Frequency converter address in 8-31 Address.
Baud rate in 8-32 Baud Rate.
Two communication protocols are internal to the
frequency converter. Follow motor manufacturer
wiring requirements.
Danfoss FC
Modbus RTU
Functions can be programmed remotely using the
protocol software and RS-485 connection or in
parameter group 8-** Communications and Options
Selecting a specific communication protocol
changes various default parameter settings to
match that protocol's specifications along with
making additional protocol-specific parameters
available
Option cards which install into the frequency
converter are available to provide additional
communication protocols. See the option-card
documentation for installation and operation
instructions