ANCA Motion AMD2000 Series User Manual Download

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AMD2000 Series D2xxx Servo Drive - User Guide

D-000088 Rev 10

ANCA Motion

7.7.6 Fault detection

Any detected fault in STO results in both STO activation, and the opening of the fault relay. The drive must be
power cycled (turned off, wait 10 seconds and turn on) before it will be able to recover from a fault. STO
incorporates both internal

and

external fault detection.

Examination of the STO inputs provides

external detection

. For correct operation of STO, both of the STO inputs

must always have the same logic level. If a difference is detected for a long enough duration, then STO is
activated and the fault relay is opened. This is intended to prevent bouncing contacts or mechanical differences
between the STO activation circuits from tripping false errors. Differences shorter than 120ms will not be detected
as a fault. Differences longer than 240ms will be detected as a fault and the fault relay will be opened. Any
duration of difference between 120ms and 240ms will result in an uncertain consequence, which may or may not
be detected as a fault. Refer to

Figure 7-23 - STO Timing Diagrams

and

Table 7-4 - STO Timing Specifications

for more details.

Examination of the power delivered to both high and low side opto-couplers to the gates provides

internal

detection

. Monitoring detects agreement in power supply levels between these two sets of opto-couplers, as well

as their independent power levels.

The fault relay is a voltage free relay output accessed via the AMD2000 I/O interface module. Do not exceed
100mA on its contacts. This output is always in the ‘closed’ position when no fault has been detected. If a fault is
tripped, the output switches to the ‘open’ position. This output is intended only for connection to an external
machine safety system or fault indicator. When a fault is indicated, the ‘open’ condition will remain and the drive
will remain in the Safe State no matter what signal is applied to the STO inputs. The only way to reset from a fault
and restore drive operation is to power cycle the drive. This is a deliberate mode of operation to ensure that the
operator is aware of any faults and cannot un-expectedly restart operation from such a fault condition.

Table 7-3 -

STO Fault Relay output ratings

describes the STO Fault Relay output requirements.

STO Fault Relay Output

(SFR-A/SFR-B)

Nominal

Maximum

Units

Voltage

24 (+20%)

VDC

Sink/source current

100

Table 7-3 - STO Fault Relay output ratings

Warning:

If any input is energised above approximately 30 V damage may occur to the drive.

This fault detection circuitry does not ensure that STO is fault free and it is up to the machine builder and
operator to ultimately ensure machine safety. A fault might only be detected when the STO is activated, for
example. This might occur in the instance when a contact on one STO input is stuck on. One input will open in
response to a demand for STO, while the stuck input will not. This is only detectable upon demand. When STO is
not being demanded this fault is no longer detectable by the drive.

Warning:

If a STO fault occurs, always test the STO feature before returning the drive back into

service

Faults in the operation of STO must be identified and logged immediately by the operator

of the machine. All faults MUST be reported to ANCA Motion, and no maintenance or repair of a
drive is allowed. Faulty drives should be returned to ANCA Motion for further evaluation.