Summa Series Servodrive Product Manual
STO
Document Version: V1.01
(Dec, 2019)
© 2019 ESTUN Automation Co., Ltd. All right reserved.
11-8
11.4.2
Safe State
When the STO function takes effect, the Drive enters the safe state and the Panel Operator displays SAF,
as is shown below.
The relationship between the State and the signals of HWBB1 and HWBB2 is shown in Table 11-2.
Table 11-2
The relationship between the State and the signals of HWBB1 and HWBB2
Item
Logic
HWBB1
ON
ON
OFF
OFF
HWBB2
ON
OFF
ON
OFF
State
－
Alarm
Alarm
SAF
Turn OFF input signals (HWBB1 and HWBB2) for taking effect the STO function, the power supplied to
the Motor will be cut off within 5 milliseconds.
ON
OFF
≤
5ms
HWBB1
HWBB2
State
Safe state
Operating state
Safety output signal from the safety controller and safety sensor may include L pulse for self-diagnosis.
Make sure the off period of safety input signal less than 1 millisecond, and the safety input circuit does
not detect this OFF event.
CAUTION
Conditions for STO function reset is that both HWBB1 and HWBB2
are ON.
