Chapter 7 Safety Function (Safe Torque Off, STO) ASDA A2-E
Revision April, 2015
7-5
7.3 Related Parameter Descriptions of STO Function
Through the setting of P2-93, users can determine FDBK status and if FDBK will latch when
STO alarm occurs. Please refer to the following figure for the setting of P2-93:
P2-93 = X X 1 0
0: Logic A
1: Logic B
2: Logic C
3: Logic D
1: FDBK no latch
2: FDBK latch
Not in use
Description of STO Function:
See the table below. Four logics (Logic A, Logic B, Logic C, Logic D) are provided to
standardize FDBK status when different STO alarm occurs. Customers can select the
corresponding logic according to the demands. (In this table, Open means FDBK+ and
FDBK- of CN8 are open circuit. Take Logic C as the example. When AL500 occurs, FDBK+
and FDBK- of CN8 are short circuited.)
Status of Servo Drive
FDBK_A & FDBK_B Status
Logic A
Logic B
Logic C
Logic D
Parameter
P2-93 XX10 XX20 XX11 XX21 XX12 XX22 XX13 XX23
FDBK Behavior
No
Latch
Latch
No
Latch
Latch
No
Latch
Latch
No
Latch
Latch
No STO alarm
occurs
Open Close Open Close
Alarm
occurs
AL500
occurs
Close Open Close Open
AL501
occurs
Close Open Open Close
AL502
occurs
Close Open Open Close
AL503
occurs
Close Open Open Close
Open = open circuit; Close = close circuit
If FDBK is latched, when STO alarm occurs, status of FDBK will remain even when the
alarm has been cleared. Please note that when more than one alarm occur, the drive panel
will only display AL500.
Example of Latch:
If Logic C P2-93 = XX22 is set, the FDBK status will be close when safety signal is lost
and AL005 occurs.
1. Since FDBK is selected as Latch, even when the safety signal is back to normal,
FDBK status still remains close. Use the approaches below to reset.
i.
Reconnect power supply. FDBK status returns to open.
ii.
Do not reconnect power supply. Instead, set P2-93=XX12 to make FDBK
status return to open. Then set P2-93=XX22 again. This step is to set
FDBK behavior to Latch.
