Troubleshooting of Siemens SIRIUS 3SK2 Safety Relay

Processing: After correcting the error, perform a reset or restart before returning to safe mode.

3.3 Logic/Wiring Error

This type of error will not result in exiting security/testing mode, but will affect the corresponding functionality.

3.3.1 Wiring Error

Performance: SF red is constantly on (to be confirmed), the status of the device depends on the current mode, and the diagnostic display screen or Safety ES can locate specific terminals.

Common scenarios: feedback circuit switch time violation, cross circuit, short circuit.

Solution: Check the wiring of the sensor/actuator, correct it, and press RESET to confirm.

3.3.2 Logical Error

Performance: SF flashing red (self confirmation), no need to reset.

Common scenarios: Discrepancy time exceeding the set value, signal sequence violating regulations.

Processing: Correct the timing of sensor actions or adjust parameters, and errors will automatically disappear.

3.3.3 Group Pre warning

Performance: SF is turned off, the DEVICE status is normal, but the diagnostic display shows a pre warning (such as waiting for start testing or triggering safety sensors).

Processing: Follow the expected operation (such as pressing the start button after closing the protective door), and the warning will be automatically released.

3.4 Parameterization or configuration errors

Stage of occurrence: Only in configuration mode.

Performance: DEVICE yellow is always on, SF red is always on, and the display screen shows "PROJ ERR" (45mm model).

Possible reasons: CRC configuration error, cycle time exceeding limit, TARGET ≠ ACTUAL configuration, invalid parameter values, interconnection rule violation.

Solution: Use Safety ES to regenerate and download the correct configuration, and release the configuration.

3.5 Handshake Error

Stage of occurrence: Only in testing mode.

Performance: DEVICE yellow is always on, SF red is always on.

Reason: The connection between Safety ES and the device is interrupted (such as cable pulling out).

Solution: Reconnect, the error disappears automatically, and the device returns to configuration mode.

Quickly troubleshoot using the diagnostic display screen (3SK26)

For systems connected to the 3SK26 diagnostic display screen, fault location is the most intuitive. The display screen is directly installed on the control cabinet door, and plaintext information can be read without opening the cabinet door.

4.1 Standard Display Interface

Status display line: device identifier, operational status (security/testing/configuration), configuration status.

If there are pending messages, the display screen will automatically redirect to the message menu and prioritize them.

4.2 Messages menu

After entering the "Messages" menu, you can view by category:

Device errors

Group errors

Bus errors - such as PROFIBUS interrupts

Group warning

Group pre warning

After selecting the specific message, right-click (OK) to view the detailed reason or directly jump to the affected functional component (such as a wiring error in input terminal F-IN5). For errors that need to be confirmed, press the left soft key (Reset) after fixing them to confirm.

4.3 Status Menu

All functional components can be listed according to the following filtering criteria:

All components

There are incorrect components

Error free components

After selecting a component (such as "Emergency Stop_1"), you can see:

Input signal status (0/1/-)

Waiting to start test flag

Violation of time difference regulations

Cross circuit detection results

4.4 System Configuration Menu

Display current hardware slot information:

Slot 2: DP interface (if present)

Slot 3: Safety Relay Body (Model, Hardware Version, Firmware Version)

Slot 4-8: Expansion module (3SK1 output expansion or 3RM1 motor starter)

This can be used to confirm whether the hardware is consistent with the configuration (such as whether the expansion module is inserted in the wrong position).

Fault response time calculation - key to safety distance assessment

In the design of safety systems, it is necessary to verify the total time (fault response time) from triggering the safety function to the complete stop of the actuator to ensure that the safety distance complies with standards (such as EN ISO 13855). The response time calculation of 3SK2 involves multiple parameters, and engineers should calculate based on actual wiring and logical configuration.

5.1 Basic Definition

Response time (fault free operation): The time it takes for an input variable to change to an output action, used to define the sequence of processes and not used for safety distance calculation.

Fault response time: the time from detecting a dangerous fault to the system entering a safe state. This time must be used for safe distance calculation.

5.2 Influencing Parameters

Typical values/setting ranges of parameter meanings

TS Sensor Response Time Refer to Sensor Manual

The time it takes for tIN input to collect logic=tCYCL (program loop time)

TCYCL program cycle time is 10-60 ms (set to 15 ms when used in conjunction with DP interface)

The timer function in tTIMER logic has a time of 10 ms~655 s (must be an integer multiple of tCYCL)

TDELAY input delay (parameterizable) 0-150 ms (must be an integer multiple of tCYCL)