GB - 15
Functional Descriptions
5. Functional Description
ThecontrolboardwiththesafetyfunctionSTOfulllsthefollowingfunctionsaccordingtoIEC
61800-5-2:
• „Safe torque off“ (Safe Torque Off – STO)
The safety-oriented switching off of the modulation is reached by a two channel disconnec-
tion of the control of the IGBT.
The 1st channel switches off the pulse pattern of the control CPU.
The 2nd switches off the supply of the gate control of the IGBT´s in the driver
The switching off of the pulse pattern and the voltage supply of the drivers are monitored.
If for example an input side connected emergency stop unit is activated (STO1 & STO2 = 0V)
it is tested by the diagnosis, if both channels have switched off the pulse generation.
In case of inactivated emergency stop unit (STO1 & STO2 = 24V) an on-off-on test is carried
out before the modulation release to ensure that a switching off is possible.
Testevery24
hours
In order to ensure safe operation, the safety function must car-
ried out every 24 hours that the on-off-on test is executed.
5.1 Switching off
After STO input voltage disconnection the control of the IGBTs is stopped within 12 ms. Re-
peated switching on is prevented for the duration of 11 ms after switching off.
5.2 Switching on
24 V on both STO inputs and a direction of rotation must be set at the control (no LS at pa-
rameter ru00) thus the on-off-on test can be executed. The frequency output is delayed by
the test about maximum 120 ms.
5.3 Error
If an error occurs during operation, the inverter turns into a „safe condition“ within 25 ms. ru00
displayes “28: Error! Safety function”.
The „Error! Safety function“ can
•notberesetbyadigitalinput
•onlyberesetbyapower-onresetofthefrequencyinverter.
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