Safety engineering
Safety functions
Safe direction
49
EDS94AYAF EN 1.0
1.3.10
Safe direction
1.3.10.1
Description
S
afe
Di
rection / SDI
This function monitors safe compliance with an adjustable direction of movement.
Monitoring also includes zero speed with a tolerance window.
If the valid direction of rotation is not complied with, optionally SS1, SS2, or STO can be
activated.
After the adjustable delay time has expired (C15341), the function monitors the
compliance with the positive/negative direction of movement.
When operating within the limit values (C15342), the "SDIxxx monitored" status is set
(C15000). The status can be assigned to the safe output (C15052/1). The status can also be
reported via the safety bus.
If deviations from the permissible direction of movement occur, an error stop will be
triggered. As an error response, STO, SS1, or SS2 can be set (C15343). In the event of an error
the maximum change in position is displayed (C15344).
Note!
If the SDI delay time (C15341) is parameterised greater than zero, either the
"SDIxxx monitored" feedback must be evaluated (safety bus or safe output) or
the risk analysis must show that the delay is not hazardous. This fact must e.g.
be considered in the calculation of the safety clearance.
Note!
If the monitoring of the direction of movement, SDIxxx, is combined with
function SLSx, the delay times must be coordinated. Then, braking time Nlim
will start at the same time as the SDI delay time.
1.3.10.2
Fault analysis
This consideration is applies to function SDI.
The position values are evaluated and checked at a cycle of 2 ms. If the defined tolerance
window is exceeded, the parameterised error response is triggered immediately within a
time slot of max. one evaluation cycle. If a SS1 or SS2 error response is triggered, the
response time of the stop function depends on the evaluation in the standard device.
Furthermore, the set stopping time must be added to the response time until the defined
operating status is reached. In the Lenze setting, the error response is set to SS1.