Rockwell Automation Publication 442L-UM005B-EN-P - April 2017 85
Technical Specifications Chapter 11
OSSD Timing Behavior
The SafeZone Mini device tests the OSSDs immediately after switch-on and
then at regular intervals. For this purpose, the SafeZone Mini device briefly
switches off both OSSDs (for 300 µs) and checks whether the OSSDs switch
to the OFF state during this time.
Figure 50 - Diagram of OSSD Test Pulses
Approximately 35 ms after the switch-on of the OSSDs, the SafeZone Mini
device performs the first voltage test (A) and then after a half basic response
time (40 ms) it performs a second voltage test (B).
After another half basic response time of the SafeZone Mini device, there is a
shutdown test (C). 120 ms later another voltage test (D). Then, the SafeZone
Mini device performs a shutdown test (C) and a voltage test (D) alternately at
an interval of 120 ms. Figure 51
, Figure 52, and Figure 53 show the pulse
duration for the individual tests.
Figure 51 - Voltage Test after Switching on the OSSDs
ATTENTION: Verify that the safety inputs on the controller that is used do
not respond to these test pulses and as a result cause the machine or system
to unintentionally shut down.
Approx.
35 ms
40 ms
120 ms 120 ms 120 ms
OSSD1
OSSD2
t
t
AC DBCD
Approx. 650 s
<300 s <300 s
OSSD1
OSSD2
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