How Does The Sto Function Work; Activation Status - Delta ASDA-B3 Series User Manual

ASDA-B3

3.9.4 How does the STO function work?

The STO function controls the motor current by two individual circuits. It cuts off the power
supply to the motor when needed, after which the motor is free from torque force. When an STO
alarm occurs, determine the alarm type according to the pin status of the feedback monitor
signal (FDBK). The following table details how this function works.
Description of action and feedback status:
Signal
source
STO_A
~ / STO_A
STO
STO_B
~ / STO_B
Servo drive output status
Feedback monitor signal
(FDBK status)
Alarm
Note:
ON = 24V; OFF = 0V.
1.
Open = open circuit; Close = short circuit.
2.
The status of the feedback monitor signal switches immediately based on the safety signal source
3.
changes.
Contact the distributor if AL503 occurs. Refer to Chapter 12 Troubleshooting for more details.
4.

3.9.4.1 Activation status

STO reaction time:
When one of the safety signal source is low, the circuit cuts off the motor current within 20 ms.
STO_A / STO_B
Safety
signal
ON
ON
Ready
Open
N/A
Motor current
ON
Status of opto-isolator
ON
OFF
Torque off
(STO_B lost) (STO_A lost)
Close
AL500
H
Max. 20 ms
OFF OFF
ON OFF
Torque off Torque off
(STO mode)
Open Open
AL501 AL502
L
OFF
Wiring
3
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