
Table 2: Error messages / flash codes red diagnostic LED
Flash codes Designation Autonomous switch-off after Error cause
1 flash pulse Error (warning) at output Y1 30 min Fault in output test or voltage at
output Y1, although the output is
disabled.
2 flash pulses Error (warning) at output Y2 30 min Fault in output test or voltage at
output Y2, although the output is
disabled.
3 flash pulses Error (warning) cross-wire short 30 min Cross-wire short between the
output cables or fault at both
outputs
4 flash pulses Error (warning) temperature too
high
30 min The temperature measurement
reveals an internal temperature
that is too high
5 flash pulses Actuator fault 0 min Incorrect or defective actuator
6 flash pulses Error actuator combination 0 min An invalid combination of
actuators was detected (blocking
bolt detection or tamper
attempt).
Continuous red signal Internal fault / overvoltage or
undervoltage fault
0 min Device defective /
supply voltage not within
specifications
6.4 Safety switch with serial diagnostic function SD
Safety switches with serial diagnostic cable have a serial input and output cable instead of the conventional diagnostic
output. If safety switches are wired in series, the diagnostic data is transmitted through the series-wiring of the inputs
and outputs.
Max. 31 safety switches can be wired in series. For the evaluation of the serial diagnostics line either the PROFIBUS-
Gateway SD-I-DP-V0-2 or the Universal-Gateway SD-I-U-... are used. This serial diagnostic interface is integrated as
slave in an existing field bus system. In this way, the diagnostic signals can be evaluated by means of a PLC.
The necessary software for the integration of the SD-Gateway is available for download at products.schmersal.com.
The response data and the diagnostic data are automatically and permanently written in an input byte of the PLC for
each safety switch in the series-wired chain. The request data for each safety switch are transmitted to the component
through an output byte of the PLC. In case of a communication error between the field bus gateway and the safety
switch, the switching condition of the safety switch is maintained.
Error
Errors which no longer guarantee the function of the safety switchgear (internal errors) cause the safety outputs to be
disabled within the duration of risk. The fault is reset, when the cause is eliminated and bit 7 of the request byte
changes from 1 to 0 or the safety guard is opened. Faults at the safety outputs are only deleted upon the next release,
as the fault rectification cannot be detected sooner.
18-22