7
CSS 34
Operating instructions
Safety sensor
EN
5.3 Safety-sensors with serial diagnostic function
Safety sensors with serial diagnostic cable have a serial input and
output cable instead of the conventional diagnostic output. If CSS
sensors are daisy-chained, the diagnostic data are transmitted through
the series-wiring of the inputs and outputs.
Max. 31 sensors 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 a 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 www.schmersal.net.
Detailed information about the use of the serial diagnostics
can be found in the operating instructions of the PROFIBUS-
Gateway SD-I-DP-V0-2 and the Universal-Gateway SD-I-U-….
Accessories SD interface
For ease of wiring and series-wiring of SD devices,
considerable accessories are available. Detailed information
is available on the Internet, www.schmersal.net.
The response data and the diagnostic data are automatically and
permanently written in the assigned input byte of the PLC for each
safety sensor in the series-wired chain. The request data for each
safety sensor are transmitted to the device through an output byte of
the PLC.
In the event of a communication error between the field bus Gateway
and the safety sensor, the switching condition of the safety output of the
safety sensor is maintained.
The following operational information is automatically and permanently
written in an input byte of the PLC for each CSS 34 sensor of the
series-wired chain
Bit 0: safety outputs enabled
Bit 1: safety sensor actuated, actuator identified
Bit 4: both safety inputs live
Bit 5: safety sensor actuated in hysteresis area
Bit 6: error warning, switch-off delay activated
Bit 7: error, safety outputs switched off
Error
A fault has occured, which causes the safety outputs to be disabled.
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. For devices with serial
diagnostic, a bit can be set/deleted in the call telegram to reset the fault.
For devices with serial diagnostic, a bit can be set/deleted in the call
telegram to reset the fault.
Error warning
A fault has occurred, which causes the safety outputs to be disabled
after 30 minutes. The safety outputs initially remain enabled. This
enables the shutdown of the process in a controlled manner. An error
warning is deleted when the cause of error is eliminated.
Diagnostic error (warning)
If an error (warning) is signalled in the response byte, detailed fault
information can be read out.
Table 2: Function of the visual diagnostic LEDs, the serial status signals and the safety outputs by means of an example
System condition
LED
Safety outputs
serial diagnostic byte bit no.
green red
yellow
Y1, Y2
7 6 5 4 3 2 1 0
Supply voltage on, not actuated
On
Off
Off
0 V
0
0
0
0
0
0
0
0
Actuated, safety outputs enabled
On
Off
On
24 V
0
0
0
1
0
0
1
1
Actuated in limit area
On
Off
Flashes
(1Hz)
24 V
0
0
1
1
0
0
1
1
Actuated, warning
On
On/
flashes
On
24 V
0
1
0
1
0
0
1
1
Actuated, fault
On
On/
flashes
On
0 V
1
1
0
1
0
1
1
0
The shown bit order of the diagnostic byte is an example. A different combination of the operational conditions will lead to a change of the bit order.
Table 3: I/O data and diagnostic data
Communication directions: Request byte:
from the PLC to the local safety sensor
Response byte:
from the local safety sensor to the PLC
Warning/error byte:
from the local safety sensor to the PLC
Bit n° Request byte
Response byte
Diagnostic
error warning
Diagnostic
error
Bit 0:
Error reset
Safety output activated
Error output Y1
Error output Y1
Bit 1:
---
Actuator detected
Error output Y2
Error output Y2
Bit 2:
---
---
Cross-wire Y1/Y2
Cross-wire Y1/Y2
Bit 3:
---
---
Temperature too high
Temperature too high
Bit 4:
---
Input condition X1 and X2
---
incorrect or defective actuator
Bit 5:
---
Actuated in limit area
Internal device error
Internal device error
Bit 6:
---
Error warning
Communication error between the field
bus Gateway and the safety switch
---
Bit 7:
Error reset
Error (enabling path switched off)
Operating voltage too low
---
The described condition is reached, when Bit = 1
