Parker AC20 Series - STO Troubleshooting

DOC-0017-04-EN: AC20 Series - Hardware Installation Manual
DOC-0017-04-EN-A 22.03.2023 83 (154)
STO Test
Step
Test Check or Activity
Expected Reaction & Effect
6
Reapply +24V to terminals STOA and
STOB and acknowledge the STO trip.
STO trip must clear.
7
Try to restart the inverter at SPT1.
Inverter must restart at SPT1.
8
Stop the inverter.
Inverter must decelerate to rest.
This test can also be automated - where the STO channels can be triggered via contacts of an external
relay.
8.7 STO Troubleshooting
The table below is for guidance only and may not be a comprehensive list of all possible symptoms relating
to STO.
Parker will not accept responsibility for any consequences arising from its incompleteness or inaccuracy.
Problem
AC20
Display
STO Input
Channel A
wrt 0V
STO Input
Channel B
wrt 0V
Possible
Cause Description
Inverter will not
run when given
a start
command
Tripped:
31 Safe
Torque
Off
< 15.0V < 15.0V
STO is
invoked.
When safe to do so, connect
STOA and STOB to a 24Vdc
supply.
Tripped:
31 Safe
Torque
Off
>15.0V &
< 25.2V
*
>15.0V &
< 25.2V
*
STO Fault
Latch may
have tripped.
Remove all power from the
inverter before re-applying.
If symptom persists,
immediately return the
inverter for repair.
Tripped:
(Any
other trip
1-30 or
32-37)
>15.0V &
< 25.2V
*
>15.0V &
< 25.2V
*
Inverter has
tripped, but
not due to
STO.
Reset the trip and remove its
cause.
If symptom persists, return
the inverter for repair.
Any other
message
>15.0V &
< 25.2V
*
>15.0V &
< 25.2V
*
Faulty
Hardware.
Return the inverter for
repair.
Inverter starts
unexpectedly
X < 5.0V < 5.0V
Faulty
Hardware.
Immediately return the
inverter for repair.
X > 5.0V > 5.0V
STO not
invoked by
the user.
Use STO in accordance with
the instructions documented
in this chapter.
Inverter fails
Comprehensive
or Regular STO
test
X X X
Faulty
Hardware.
Immediately return the
inverter for repair.
*
26.4V in a maximum operating ambient of 40°C