When the STO safety function is active, the power supply
is safely interrupted by two separate shutdown paths to the
motor in the tool. The motor can not produce any torque
and therefore no dangerous movements. There is no moni-
toring of the standstill position. This is relevant, for exam-
ple, for torques generated by loads, such as suspended
loads, or by preloaded spring drives. In such cases, addi-
tional measures for shutdown must be provided that pre-
vent these reactions - these must be ensured and brought
about in a safety-related manner.
Caution
There is a risk of the motor starting up when
there multiple errors in the controller.
If the final stage of the nutrunner module
in the controller fails during the STO state
(simultaneous short circuit of 2 power
semiconductors in different phases),
there may be a limited locking movement
of the rotor in the motor. The angle of ro-
tation corresponds to a pole pitch, which
acts on the output drive with the gear re-
duction. The angle of rotation for electric
hand tools from Cleco Production Tools is
always ≤15°.
9.2.1 Diagnostic Coverage (DC)
The Diagnostic Coverage depends on the inclusion of the
integrated safety function for the controller into the
controller chain, as well as the implemented measures for
the diagnostics.
If a fault is detected during the diagnostics, suitable mea-
sures must be provided to maintain the safety level.
9.2.2 Interface overview
The STO safety function for the controller is controlled via
the digital I/O interfaces X41, X42. The interfaces for all
controllers with the STO function are designated the same,
color-coded and functionally identical with the same speci-
fications, see 5 Pin Assignment, Page 12.
The STO safety function is requested exclusively via the
two digital control inputs STO-A and STO-B. Another con-
nection of the signals, e.g,. feedback or auxiliary voltage, is
not absolutely required.
Note
Cross-connection detection of the input cir-
cuit is not performed by the controller.
All system components allow the short cir-
cuit fault exclusion.
The state of the STO safety function is reported back via a
potential-free feedback contact (closer). This information is
linked in a successive circuit of several controllers with the
STO function.
Apex Tool Group
Interface port X41 – IN
Depending on the position of the currently considered con-
trol in the STO line (see 11 System, Page 114), the inter-
face port X41 is the connection to the previous controller or
to the external safety relay.
By providing an auxiliary power supply of 24 VDC in con-
nector X41, it is possible to supply the voltage to safety
relays for normally open contacts, or similar.
Pin
Signal
1
24 VDC
2
24 VDC
3
FB-1-In
4
STO-A
5
GND_STO
6
STO-B
7
FB -2
8
GND_STO
Interface port X42 – OUT
Depending on whether the currently considered controller
is the last in an STO line, or whether another controller fol-
lows, the interface X42 is the connection to the next
controller or can be left without connecting further. If the
feedback contact is evaluated, a termination on the last
controller in a line is necessary.
P2552HW | 2021-04
Description
Output auxiliary power supply 24
VDC, for passive control of STO
Reference potential is GND_STO
Potential-free Feedback Contact 1
(informative) for the STO state
•
Feedback contact open: STO not
active
•
Feedback contact closed: STO
active
Input for control signal A for con-
trolling the STO safety function
Reference potential is GND_STO
•
STO request at low level simulta-
neously with low level at STO-B
Reference potential for all voltages at
X41
Input for control signal B for con-
trolling the STO safety function
Reference potential is GND_STO
•
STO request at low level simulta-
neously with low level at STO-A
Potential-free Feedback Contact 2;
for a description, see FB-1
Reference potential for all voltages at
X41
1
EN
17