Safety reaction time, Considerations for safety ratings, Considerations for single-encoder applications – Rockwell Automation 2094-EN02D-M01-S1 Kinetix 6200 and Kinetix 6500 Safe Speed Monitoring Safety Reference Manual User Manual
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Rockwell Automation Publication 2094-RM001C-EN-P - May 2013
Chapter 1
Safety Concept
Safety Reaction Time
The safety reaction time is the amount of time from a safety-related event as
input to the system until the system is in the Safe State.
The safety reaction time from an input signal condition that triggers a safe stop,
to the initiation of the configured Stop Type, is 20 ms (maximum).
The safety reaction time from an overspeed event that triggers a safe stop, to the
actual initiation of the configured Stop Type, is equal to the value of the
[Overspeed Response Time] parameter.
For more information on overspeed response time, see
Considerations for Safety
Ratings
The achievable safety rating of an application that uses safe speed monitoring is
dependent upon many factors, including the encoder setup, drive options, and
the type of motor.
When using two independent encoders to monitor motion and when installed in
a manner to avoid any common cause dangerous failure, the Kinetix 6200 and
Kinetix 6500 drives can be used in applications up to and including SIL CL3,
PLe, and CAT 4.
For applications that rely on commutation to generate torque and motion, a
safety rating up to and including SIL CL3, PLe, and CAT 4 can be achieved.
Considerations for Single-encoder Applications
When configured correctly, the Kinetix 6200 and Kinetix 6500 drive performs
these diagnostics on the encoder:
• Sin
2
+ Cos
2
diagnostic
• Detection of open or short-circuit
• Encoder supply voltage monitoring
• Detection of illegal quadrature transitions of the sine and cosine signals
IMPORTANT
Some of the diagnostics performed on the encoder signals require motion to
detect faults. You must make sure that motion occurs at least once every six
months.