
Safety engineering
Safety functions
Safe maximum speed
46
EDS94AYAF EN 1.0
1.3.8
Safe maximum speed
1.3.8.1
Description
S
afe
M
aximum
S
peed / SMS
This function monitors the maximum motor speed. If a value > 0 is indicated (C15320), the
function is activated.
If the maximum speed is exceeded, a error stop is caused. STO, SS1 or SS2 (C15321) can be
adjusted.
1.3.8.2
Fault analysis
This consideration applies to the SMS and SLS functions.
The evaluation and plausibility of the speed values is done in a cycle of 2 ms.
If the defined limit values are exceeded, the parameterised error response is activated
within a time slot of maximally one evaluation cycle. With the error response SS1 or SS2
the response time of the stop function depends on the evaluation in the standard device.
Moreover, the set stopping time must be added to the response time until the defined
operating status is reached.
In order that the response can be checked for an error as quickly as possible, a maximum
response time (C15350) can be parameterised. Before the maximum response time has
elapsed, the detected speed must comply with the permissible (monitored) speed. If the
permissible (monitored) speed is not complied with, STO is activated immediately.