Description of Q951+Q984
Contents of this chapter
This chapter contains a description of the safety function. This chapter also shows the
settings related to the safety function.
Overview
The emergency stop function with push button monitoring (Q951+Q984) corresponds
to an uncontrolled stop in accordance with stop category 0. This emergency stop function
does not have a SIL/PL classification.
In this emergency stop function, the drive has two different safety circuits:
• the primary safety circuit that consists of the emergency stop button (optional in ACS880
multidrives), the relays, and the contacts wired to them. The emergency stop button
activates the emergency stop function when pushed. Line faults in the primary safety
circuit will cause the emergency stop function to activate.
• the user-implemented push button circuits, which are connected to the push button
monitoring relays. The push buttons activate the emergency stop function when pushed,
but line faults in the push button circuits will not cause the emergency stop function to
activate.
You can connect push buttons to the push button monitoring relays. The push button
monitoring system monitors the status of each button. If there is a fault (for example, a short
circuit or damaged wire) in a push button circuit, the emergency stop function is not activated,
but the main monitoring relay opens a normally-closed relay contact. You can use the relay
contact to implement a fault indication system.
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Description of Q951+Q984 15
