Baumuller BUM64A, Manual

Page: 109 / 120

Safety relay
Manual Single Power Unit BUM64S/A/F
Document no.: 5.01056.03
109
of 118
E
the safety function, whereat not the complete possible errors can be self-contained recognized
by the system. Therefore an accumulation of unrecognized errors can lead to a loss of the safety
function.
Category 4 accords to the level “Self-monitoring”. This component recognizes self-contained
possible errors and signals these in time of the loss of the safety function. Also if up to three from
one another independant errors arise the safety function is always maintained.
E.3 The safety relay
The function of the safety relay is executed in fail-safe-technic, also named closed-circuit prin-
ciple. The safety function “safe stop” is active, as long as no voltage is applied to the input ter-
minals (X68: 3,4). Consequently the functioning of the safety function is guaranteed if power
failure takes place. In order to deactivate “safe stop” a voltage of 24 V has to be applied to the
terminals, which are intended for this use (X68: 3,4).
For the external error monitoring of the safety relay´, the instantaneous control state can be in-
terrogated at its positively driven status signal contact (X68: 1,2). In case there is no voltage
applied to the safety relay (X68: 3,4), that means during the “safe stop”, then the status signal
contact is closed (NC contact). Also a parting of a cable can thusly be recognized as an error.
If the voltage at the input terminals of the relay (X68: 3,4) is switched off, then the converter gen-
erates one or two error messages (F0204 and/or F0206), which it displays on the V-controller.
The drive can only be taken in operation again, if these messages are deleted after a reset of
the safety relay with a reset signal from the controller (for example by X26, pin programmable
or over the interface to a bus system).