MX2 Quick Start Guide 21
PROGRAMMING MX2
3.8 DC Braking
The DC braking feature can provide additional stopping torque during deceleration or before acceleration and is particulary use-
ful at low speeds when normal deceleration torque is minimal. This function injects a DC voltage into the motor windings which
generates a DC current that force the motor to stop.
There are several modes available depending on the application requirements:
• Normal DC braking is used when A051 is set to “01” (Enable during stop) and the RUN command (FW/RV) is turned OFF,
at the moment that deceleration stops the DC brake starts with a settable power (A054) and duration (A055). Additionally is
possible to specify a wait time between the end of the ramp and the DC braking on parameter A053, during which the motor
will free run. If free-run is selected as stopping method the DC braking will start just when the Run commands turns OFF.
• DC braking by frequency detection can be selected setting a051 to “02” (Frequency detection). In this case DC braking oper-
ates when the output frequency comes down to the one you specified in A052 while the RUN command is still active. Exter-
nal DB and internal DC braking are invalid during the frequency detection mode.
• Last option is to trigger the DC injection by a digital input when the terminal (DB) is turned ON. Set parameters A053 and
A054 to setup this function. There are several cases depending on the motor rotation and Run command status.
ON
F-SET
A053
DB
DC Brake at stop
F-OUT
A054
A055
FW
FW
ON
F-SET
A052
DB
Eample 1: Step change in F-SET
F-OUT
FW
ON
F-SET
A052
Example 2: Analog change in F-SET
F-OUT
DB DB DB
[FW,RV]
1
0
[DB]
1
0
F-OUT
FW or RV DI are ON
t
1
0
1
0
t
1
0
1
0
t
delay
A053
Run from operator
Run from operator with delay
I129E-EN-02+MX2+QuickStartGuide.book Seite 21 Mittwoch, 7. November 2012 1:54 13
To Next Page
Loading...
