Delta EB3000 Series User Manual page 84

Circuit without operation contactors that complies with EN81-20
The STO circuit is installed in an elevator system that does not use any operation contactors. In
such a system, the following guidelines must be followed to comply with EN81-20.
 Circuits must be designed in order to deactivate input terminals STO1 and STO2 inputs
when the safety circuit is OFF, and disable the drive output.
 STO inputs (terminals STO1 and STO2) must be used to enable / disable the drive.
NOTE:
1. Once input terminal STO1 or STO2 is OFF, the drive output will immediately stop. In this case, use brake
immediately to prevent the elevator from moving.
2. Input terminals STO1 and STO2 must be ON before setting the Up/Down command. The elevator controller can give
the Up/Down command only when it receives the signal that the STO monitoring output SMO (SMO+, SMO-) is OFF.
3. After the elevator stops, STO1 and STO2 should be OFF. The elevator controller must receive the signal that the
STO monitoring output SMO (SMO+, SMO-) is ON, if not, STO circuit sticking may occur and the elevator cannot be
started again.
4. The contactor monitoring circuit in the elevator controller can be changed to monitor STO monitoring output SMO
(SMO+, SMO-).
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Chapter 4 WiringEB3000
Figure 4-28