Siemens SINUMERIK 840C - Manual (Page 992)

10.94 12 Functional Descriptions
12.20.4 Mains buffering and mains failure detection 611A/D
12.20.4.4 DC link undervoltage monitoring in 611D
With the 611D package 2, the user can parameterize a new threshold for DC link voltage
monitoring (drive MD 1634). The DC link voltage monitoring function via drive MD 1604, which
is already available with package 1, is not relevant for the "Extended stop and retract"
function since the drive reacts immediately with cancellation of SIMODRIVE_READY and
DRIVE_READY.
Detection of a drop in the DC link voltage to below the threshold parameterized in drive (611D)
MD 1634 can be used as an internal error source (axis/spindle-specific NC-MD bit) for the
retraction operation. In this way, it is possible to prevent the drive hardware from being shut
down when the DC link voltage drops below the minimum limit (280V) before the workpiece
and tool have been separated.
By setting an NC-MD bit, it is also possible to parameterize for one or several axes
(meaningful for one axis per I/RF range) whether a retraction operation is to be initiated when
the DC link voltage drops below the threshold set in drive MD 1634. If the "Extended stop
and retract" function is parameterized and programmed, this function is then executed if it
has been enabled via the PLC NS signal "Retraction enabled".
Through appropriate parameter settings in NC = MD 529* and 592*, it is possible to program
either the autonomous drive or the open-loop control reaction. It is advisable to program the
autonomous drive reaction if the high dynamic requirements of the drive(s) involved are such
that the energy available is not sufficient to successfully separate the positive connection for
"Extended stop and retract" as an open-loop control function (reaction and execution time
too high). However, this setting has the disadvantage that interpolative retraction and stopping
cannot be implemented.
The DC link can be supplied with additional energy required for "Extended stop and retract"
by means of a parallel, regenerative braking operation:
See DC link buffering.
Monitoring of DC link voltage for violation of voltage threshold in drive MD 1634
Drive
MD 1634
V
DClinkOFF
600V/625V
280V
ZK2 message:
DC link voltage < drive MD 1634
SIMODRIVE "OFF"
t
V
DClinkrated
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 12–217
SINUMERIK 840C (IA)