Intended Use Of The Sto Function; Safety Characteristics; Foreseeable Misuse Of The Sto Function; Diagnostic Coverage (Dc) - Festo EMCA-EC-67 Serie Traducción Del Manual Original

EMCA-EC-67-...
1.1.2

Intended use of the STO function

The EMCA supports the STO safety function (Safe torque off/STO) in accordance with EN 61800-5-2.
The STO function is intended to disconnect the torque from the integrated motor and prevents the un­
expected restart of the motor. The STO function may only be used for applications in which the spe­
cified safety characteristics suffice.
1.1.3

Safety characteristics

The STO function of the integrated drive EMCA satisfies the requirements for the following safety char­
acteristic values:
– PL d/cat. 3 in accordance with EN ISO 13849-1 (Performance Level/PL)
– SIL 2 in accordance with EN 61800-5-2 (Safety Integrity Level/SIL)
– SIL CL 2 in accordance with EN62061 (Claim Limit/CL)
The achievable safety level depends on the other components that are used to implement the safety
function.
The device must be activated via the connection [X6] with the category required for the application in
accordance with EN ISO 13849-1, e.g. via an external safety relay.
1.1.4

Foreseeable misuse of the STO function

Unintended use includes the following misuses:
– Bypassing of the safety function
– Applications where switching off can result in hazardous movements or conditions
The STO function does not provide protection against electric shock, only against dangerous move­
ments!
1.1.5

Diagnostic coverage (DC)

Diagnostic coverage (è Chapter 4) depends on how the device is integrated in the control chain and on
the measures implemented for the diagnostics.
In order to achieve the specified diagnostic coverage, the status of the acknowledgment contact must
be evaluated by the control system every time the STO function is requested.
If the signal of the acknowledgment contact does not have the expected value, a potentially dangerous
malfunction may exist. In this case, appropriate measures must be implemented to maintain the safety
level.
Note
The EMCA cannot detect a cross circuit in the input circuit by itself.
• Find out if cross-circuit detection is needed for the input circuit and wiring in your
application.
• If required, use a safety switching device with cross-circuit detection.
26 Festo – EMCA-EC-67-... – 1603 English