Functional safety
326
9.
FUN
C
TI
ON
AL SAFET
Y
STO safety
function
314
DDS
HARDWARE
Ref.1310
9.1 STO safety function
The STO (
S
afe
T
orque
O
ff)
is the only safety function Fagor Automation
drives AXD/SPD offer according to the standard IEC 61800-5-2.
This safety function may be used to safely disconnect the motor torque and
it is always active.
STO first channel
It is the external main contactor
- KM1
that will remove input power to the
power supply (PS, XPS or RPS). To perform the monitoring, the contactor
has to have an N.C. contact (
N
ormally
C
losed) that complies with IEC
60947-4-1 or with IEC 60947-5-1.
STO second channel
It is
pin 2 “Drive Enable”
of connector X2 of the AXD/SPD, that will dis-
able motor torque. The N.C. contact (
N
ormally
C
losed) may be monitored
through pins AS1, AS2 of connector X7.
PL d or SIL 2
When a machine requires a PL d or SIL 2, it requires an external safety
controller PL d or SIL 2 that disconnects the motor torque in the two chan-
nels. The safety controller must watch the status of each channel (only
when demanded by the STO) keeping the motor torque off in case of fail-
ure.
Safe state
The safety controller may use the “Torque OFF” state to achieve a safe
state of the machine.
Brake
Requesting the STO safety function while the servo system is moving,
and there is no brake causes the motor to only stop by friction (coasting).
If there are external forces on to the motor (e.g. vertical axis), where an
unwanted movement (e.g. due to gravity) can cause a risky situation, this
must not be used without additional measures to protect against dropping.
A risk analysis of the machine may require a brake to help stop the motor.
Failure reaction and failure reaction time
After a request from STO, if one of the channel fails, its corresponding
feedback contact opens. The safety controller does not allow engaging
the system and consequently, the failure reaction time is zero. Do not mis-
take it with the response time of the STO function itself that could be of
some ms. See
.
Summary of Contents for DDS
Page 1: ...DRIVE DDS Hardware manual Ref 1310...
Page 6: ...I 6 DDS HARDWARE Ref 1310...
Page 9: ......
Page 10: ......
Page 11: ......
Page 12: ......
Page 16: ...16 Ref 1310 DDS HARDWARE...
Page 30: ...1 DESCRIPTION 30 Description DDS HARDWARE Ref 1310...
Page 94: ...2 POWER SUPPLIES 94 Power supplies DDS HARDWARE Ref 1310...
Page 188: ...3 DRIVE MODULES 188 Drive modules DDS HARDWARE Ref 1310...
Page 204: ...4 AUXILIARY MODULES 204 Auxiliary modules DDS HARDWARE Ref 1310...
Page 232: ...SELECTING CRITERIA 5 232 Selection criteria DDS HARDWARE Ref 1310...
Page 266: ...7 CABLES 266 Cables DDS HARDWARE Ref 1310...
Page 312: ...8 INSTALLATION 312 Installation DDS HARDWARE Ref 1310...
Page 326: ...9 FUNCTIONAL SAFETY 326 Functional safety DDS HARDWARE Ref 1310...
Page 354: ...10 CONNECTION DIAGRAMS 354 Connection diagrams DDS HARDWARE Ref 1310...
Page 378: ...12 SALES REFERENCES 378 Sales references DDS HARDWARE Ref 1310...
Page 384: ...13 COMPATIBILITY 384 Compatibility DDS HARDWARE Ref 1310...
Page 385: ......