Siemens SINUMERIK 808D Function Manual page 198

WARNING
Appropriate measures must be taken to ensure that the motor does not undesirably move once the energy feed has been
disconnected, e.g. against coasting down.
CAUTION
If two power transistors simultaneously fail in the power unit (one in the upper and one in the lower bridge), then this can
cause brief momentary movement.
The maximum movement can be:
Synchronous rotary motors: Max. movement = 180 ° / No. of pole pairs
Synchronous linear motors: Max. movement = pole width
Note
Closing delay of the holding brake
The closing signal (low level) of the holding brake is output 30 ms after the STO is triggered.
Preconditions for using the STO function
When use the STO function, the following preconditions should be fulfilled:
● Each monitoring channel (STO1 and STO2) triggers safe pulse suppression with its switch off signal path.
● If a motor holding brake is connected and configured, the connected brake is not safe because there is no safety function
for brake, such as safe brake.
Behaviors of the STO function
Terminal
STO1 STO2
High level High level
Low level Low level
High level Low level
Low level High level
Control circuit interfaces - drive side
Type
Safe Torque Off (STO)
interfaces
Control power input
interfaces
1)
Maximum connectable cross-section: 1.5 mm
Maximum current consumptions without brake power supply and with brake power supply are respectively 1 A and 3 A.
1)
Wiring
Note
Using the STO function
The STO1, STO+ and STO2 are short connected at the factory setting.
When the STO function is to be used, you must remove the short-circuit stick before connecting the STO interfaces. If you
do not need to use it any more, you must reinsert the short-circuit stick; otherwise, the motor will not run.
198
State
Safe
Safe
Unsafe
Unsafe
Illustration
2
Action
The servo motor can normally run when you power on the servo
drive.
The servo drive starts up normally but the servo motor cannot
run.
Alarm occurs and servo motor coasts down.
Alarm occurs and servo motor coasts down.
Signal Description
STO 1 STO 1: coast down
STO + STO +: 24 VDC
STO 2 STO 2: coast down
+24 V Power supply 24 VDC (without brake: -15% to
+20%, with brake: -10% to +10% )
Power supply 0 VDC
M
Function Manual
01/2017