Safe Torque Off (Sto); Global Sto, Control Via Akd-C; Local Sto, Control Via Digital Input On Akd-N-Ds; Safety Characteristic Data - Kollmorgen AKD-N00607 Installation Manual

AKD-N Installation | 6 Technical description and data

6.14 Safe Torque Off (STO)

The STO functionality of AKD-N with option "DB" or "DF" is controlled by the AKD-C smart
power supply via the specific string, where the AKD-N is connected to. This STO topology is
called "Global STO" or "String STO".
AKD-N drives with option "DS" offer an additional connector X6 with a digital STO-Enable
input. This STO functionality is called "Local STO". These drive variants cannot be safety
controlled by the global STO functionality.

6.14.1 Global STO, control via AKD-C

Connector X16 on the AKD-C offers access to all STO (Safe Torque Off) signals of the
decentral drive system powered by this AKD-C . There is one STO-Enable input and one
STO-Status output for each DC Power string.
The global STO function is described in the AKD-C Installation Manual. Application
examples can be found in the Decentralized System Projecting Guide.
The global STO function uses the following devices: AKD-C, AKD-N without option "DS",
Kollmorgen hybrid connection cable.
In case of using an AKD-N with option "DS" (local STO input), the global STO-Enable signal
will have not influence to this specific drive. The local STO-Status of this drive nevertheless
is monitored in the string STO-Status.

6.14.2 Local STO, control via digital input on AKD-N-DS

Option "DS" on the AKD-N offers local STO-Enable functionality. There is one STO-Enable
input on X6 and one STO-Status output on X3 for the drive. The STO-Status outputs on X3
are available only with AKD-N drives with option "DS".

6.14.3 Safety characteristic data

The subsystems are described with the following characteristics:
Device
A very unlikely but possible event can happen, if within a very short time 2 not adjacent
IGBTs will have a short circuit. In such case a movement of maximum an angle of 120° (elec-
trical) can happen. This effect can only happen if the drive is in the function STO. If the total
failure rate of the IGBT is 120 fit normally for such short circuit 60 fit will be valid (50:50
model). By such event 2 specific IGBTs have to fail at same time. The calculation shows a
probability of 1.5 * 10
will be issued for a whole year, this event will only happen every 100 Billion years.
36 Kollmorgen | December 2014
Operation ISO 13849-1
Mode
STO STO single PL d, CAT 3
channel
-15
per hour (without common cause failure). Even if the STO function
IEC 62061 PFH T
M
[1/h]
SIL 2 i.p.
[Years] SFF
[%]
i.p. i.p.