Cleco mPro300GCD-STO Serie Descripción Del Hardware página 19

contacts, the level changes never occur at exactly the same time. This is tolerated by the so-called discrepancy time as
long as the level changes occur within this time. If the levels of the control signals STO-A and STO-B are different for
longer than this time, a transition is made to an error state that can not be reset. The discrepancy time Δt is 100 ms. This
can not be parameterized.
The signals STO-A and STO-B should be switched simultaneously if possible.
Test pulses
Test pulses from safety controllers are not tolerated and must be deactivated for system availability. The exclusive use of
Cleco accessories allows the short circuit fault exclusion.
Feedback contact FB
The feedback contact indicates the safe state. If the STO safety function is not active, then the feedback contact is open.
This is also the case, for example, when the 24 V logic supply voltage is switched off due to a defect or a failure of the
supply voltage. When the STO safety function is active, the relay contact is closed.
Note
The feedback contact has a single-channel design and may be used for diagnostic purposes, but
not in the safety circuit.
► When switching on, the feedback contact may briefly deviate from the input signals until the control-
ler is ready for operation.
The following table shows the state of the feedback contact, depending on the input signals and the time. A precondition
is always the error-free state (Row 1 or 4). The time Δt is the discrepancy time 100 ms.
Row STO-A
1 0
2 0
3 1
4 1
Overvoltage and polarity reversal protection
The control inputs STO-A and STO-B are protected against overvoltages and against the polarity reversal of the control
voltage, see chapter 9 Technical Data, page 22.
The 24 VDC auxiliary voltage supplied at X41 is short-circuit proof. However, a short circuit or overload leads to the fail-
ure of alll the internal logic voltages and thus to the failure of the primary function.
8.5 Diagnostics
The STO safety function is monitored in the controller for plausibility and operability.
STO status signal to control
Within the software, the status of the STO safety function (1=OK, 0=STO triggered) is available at Input 10 on the I/O
level under device TM_DIDO.
If this status information is present in the application, this must be assigned accordingly by the operator. It is advisable to
use the software input Emergency Stop. Assignment is not necessary for safety reasons.
Fail-Safe state
If a fault in the safety technology is detected, e.g., if, for example, control signals STO-A and STO-B have unequal levels
or there is a circuit defect, then a fault is triggered internally. This fault can not be reset or can only be reset by a restart,
i.e., further start attempts no longer lead to the turning on of the output drive.
It is assumed that there is an external fault and the controller must be switched off. If the fault persists after checking the
external controller, then there is a defect in the controller and it must therefore be replaced.
8.6 Time response
The control signals STO-A and STO-B are equivalent in regards to their use, although the signals operate different shut-
down paths. They are described in terms of the time response as a single, exchangeable STO signal.
Apex Tool Group
STO-B FB closed
0
1
0 → Δt → 1
1
P2552HW | REV D l 2023-12
Leads to diagnostic error after Δt
1
0
0
1
EN
0
→ Δt → 1
→ Δt → 1
0
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