Functional Software description
76
DCS 500 Software Description
•
Brake Control
Specific drives such as hoisting or travelling drives must keep in
their current position even the regulator switched off. Control of the
brake and converter has to be synchronised to avoid moving of
load when the brake is released. The motor has to produce a
holding torque before a release command is given to the brake.
DCS 500B has a full sequence control for a mechanical brake pro-
vided by the BRAKE CONTROL function block. It is designed to
operate in co-operation with speed controller.
Safety
If a fault has occurred or watchdog trips in control board
SDCS-CON-2, the brake is immediately controlled to close
state
(
LIFT BRAKE (10304) = 0
).
If emergency stop is activated, the function of brake can be defined
by parameter
EMESTOP BRAKE (307)
:
0
= DISABLE (brake is closed when speed is zero)
1
= ENABLE (brake is closed immediately)
BRAKE_CONTROL
function block
Holding Torque
Holding torque reference can be connected to input
[HOLD REF]
(301)
from the application or analog input. If constant holding tor-
que is used, it can be set with parameter
HOLD TORQ (307)
. If
[HOLD REF] (301)
is not connected, the reference is defined by
parameter
HOLD TORQ (307)
.
Brake Release
The mechanical brake is released by means of input
[BR RELEASE] (302)
. The RUN command from the output of di-
gital input is normally connected to here.
Minimum Speed
Indication
Input
[MIN SP IND] (303)
is the minimum speed indication for the
block. This input should be active when actual speed of the drive is
below the minimum speed limit. Minimum speed indication is avai-
lable from the SPEED MONITOR function block or it can be
generated by external device or DCS 500B function block application
Brake Acknow-
ledge
The brake released acknowledge can be connected by means of
digital input to input
[ACK BRAKE] (304)
in BRAKE CONTROL
function block. Otherwise acknowledge is done in software by con-
necting
[ACK BRAKE] (304)
directly to brake release command
LIFT BRAKE (10304)
.
Summary of Contents for DCS 500B
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