Safety Input Properties - Danfoss iC7 Series Operating Manual

Operating Guide | iC7-Automation Functional Safety

Safety Input Properties

4.3.4
For flexible adaptation to the safety system, the safe inputs contain the following properties:
Galvanic isolation of terminals: The functional safety I/O terminal blocks on the control board have separate, galvanically isolated
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inputs to allow, for example, interchanging of the polarities of the safe input terminals as shown in
Test pulse filtering: Several control modules test their safe outputs using Test Pulse Pattern (on/off tests) to identify faults due to
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either short- or cross-circuiting. When interconnecting the safe input of the drive with a safe output of the control module, the drive
responds to the test signals. A signal change during a test pulse pattern is configured with parameter Stable Signal Time (range 1–
5000 ms). Test pulses of the length configured in parameter Stable Signal Time are ignored on the safe input lines. It is also possible
to filter short pulses, which could lead to safety functions being activated incorrectly.
See 4.4.2 General Functional Safety Parameters
The stable signal time extends the safety function response time. The safety function is activated after the response time has
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expired.
If the signal to the safety input is not stable, the drive responds with a fault.
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2 ms max.
Safe Input Ch. A/B
Safety function
Active
Inactive
Figure 9: Test Pulse Filtering
Asynchronous input tolerance: The input signals at the safe input terminals are not always synchronous. If the discrepancy
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between the 2 signals is longer than 500 ms, the drive indicates an IO failure as described in
Signal. This feature does not delay the activation of the safety function.
28 | Danfoss A/S © 2024.08
for more information on parameter Stable Signal Time.
NOTICE
Test pulse STO demanded
Time
Debounce time
Time
Functional Safety for Frequency Converters, Upgradable (+BEF2)
4.10.2 Instances of the STO Feedback
Figure 9 and Figure 10.
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