Mechanical Brake Control; Rs485 Serial Communication - Danfoss VLT AutomationDrive FC 301 Operating Instructions Manual

Electrical Installation

4.8.5 Mechanical Brake Control

In hoisting/lowering applications, it is necessary to
control an electro-mechanical brake.
•
Control the brake using any relay output or
digital output (terminal 27 or 29).
•
Keep the output closed (voltage-free) as long as
the frequency converter is unable to keep the
4 4
motor at standstill, for example due to the load
being too heavy.
•
Select [32] Mechanical brake control in parameter
group 5-4* Relays for applications with an electro-
mechanical brake.
•
The brake is released when the motor current
exceeds the value in parameter 2-20 Release Brake
Current.
•
The brake is engaged when the output frequency
is less than the frequency set in
parameter 2-21 Activate Brake Speed [RPM] or
parameter 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
overvoltage situation, the mechanical brake immediately
closes.
NOTICE
The frequency converter is not a safety device. It is the
responsibility of the system designer to integrate safety
devices according to relevant national crane/lift
regulations.
L1 L2
Frequency converter
U V
Motor
Illustration 4.11 Connecting the Mechanical Brake to the
Frequency Converter
20
VLT
L3
Output
relay
W
02 01
Mechanical
brake
Output
A1
contactor
input
Shaft A2
Brake power circuit
380 V AC
Danfoss A/S © 07/2015 All rights reserved.
®
AutomationDrive FC 301/302

4.8.6 RS485 Serial Communication

Connect RS485 serial communication wiring to terminals
(+)68 and (-)69.
•
Use screened serial communication cable
(recommended).
•
See chapter 4.3 Grounding for proper grounding.
Illustration 4.12 Serial Communication Wiring Diagram
For basic serial communication set-up, select the following:
1. Protocol type in parameter 8-30 Protocol.
2. Frequency converter address in
parameter 8-31 Address.
3. Baud rate in parameter 8-32 Baud Rate.
•
2 communication protocols are internal to the
frequency converter:
•
Functions can be programmed remotely using
the protocol software and RS485 connection or in
parameter group 8-** Communications and
Options.
•
Selecting a specific communication protocol
Command circuit
changes various default parameter settings to
220 V AC
match that protocol's specifications and makes
additional protocol-specific parameters available.
•
Option cards for the frequency converter are
Frewheeling
available to provide additional communication
diode
protocols. See the option card documentation for
installation and operation instructions.
61
68 +
RS-485
69
- Danfoss FC.
-
Modbus RTU
MG33AQ02