Siemens SIMODRIVE POSMO A

5
5.5 SIMODRIVE POSMO A functions
5-191
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SIMODRIVE POSMO A User Manual (POS1) – 08/2013 Edition
The ”pulse enable” is withdrawn when the following events occur:
 STW.1 (operating condition/OFF 2) = 1/0 signal
 STW.3 (operation enabled/operation inhibited) = 1/0 signal
 A fault occurs, where it is no longer possible to brake in a controlled
fashion (e.g. encoder fault)
What happens if the ”pulse enable” is withdrawn?
When the pulse enable is withdrawn, the drive coasts down, and the
”open holding brake” output signal is canceled.
The motor ”coasts” down until the brake becomes effective mechani-
cally and brings the motor to a standstill.
After the time taken for the brake to close, the drive is braked by the
motor holding brake.
Speed actual value
Output signal
”control external
holding brake”
Holding brake
”Pulse enable”
ÄÄÄÄÄ
ÄÄÄÄÄ
t
t
t
t
t
The drive ”coasts” down
The drive is braked by the
holding brake
Speed setpoint
Time
to close the holding brake
1
0
1
0
1
0
Positioning mode OFF 2 – operating inhibit – fault
Fig. 5-19 Closing the brake: Behavior when withdrawing ”pulse enable”
!
Warning
When this type of braking is used, it subjects the holding brake to
mechanical wear and therefore should only be seldomly used.
Closing the brake
when the ”pulse
enable” is
withdrawn
5 Description of the Functions
02.9904.01