HB-37420-810-01-25F-EN SMX100 Installation manual.docx Page 104 of 260
Version: 25F
4.3.3 Permissible capacitive and inductive load at safe outputs
The safe outputs of the SMX100 exhibit an OSSD character. That is, the outputs are cyclically
switched off for the test of the switching off ability and the status is read back.
The examination of the switching off ability takes place according to the following
criteria/functions:
- After switching the output off, the output voltage may max. be 5.6 V
- The permissible voltage level must be achieved at the latest after 400 µs
- If the permissible voltage level is reached, the test is seen as successful, the output is
activated again without further delay
- If the permissible voltage level is still not reached after 400 µs, an alarm is triggered and
all safe outputs (second channel with safe outputs!) are deactivated
The following representation shows the ideal (green curve) and typical (red curve) process.
For the determination of the maximally permissible capacity or inductance, the time constant of
the real RC or RL member at the output must be viewed.
This RC or RL member determines the real discharge curve:
The voltage level of max. 5.6 V is securely reached after 3 .
It thus applies:
3 < 350µs
< 100µs
With that connection
the max. usable capacitive or inductive load can be determined in connection its Ohm's load:
or
Typical values for the capacity C are C=20 nF and for longitudinal inductance L = 100 mH
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