Siemens SINUMERIK 840D Description Of Functions page 445

11.03
The "position controller active" signal (DB3x.DBX 61.5) represents a further
condition to release the brake. The "speed controller active" signal (DB3x.DBX
61.6) should be used in conjunction with Safety Integrated, because when
Stop C is active the position controller is inactive but the speed controller
remains active, which means that the drive would work in opposition to the
brake.
8.2 Two-channel brake control with SI (SPL)
Description In order to increase the safety-relevant quality of the brake control system (for
the holding brake or operating brake), it is necessary to use a two-channel
control system. An NCK output switches the P voltage (24 V) to release the
brake and a PLC output (S7 relay module) switches the M voltage (P/M
control). A checkback contact on the PLC side verifies that the two switching
elements are operating correctly.
Controlling the NCK output (relevant signals – suggestion):
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•
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Connecting these signals to $A_OUTSE (NCK output)
Controlling the PLC output (relevant signals – suggestion):
Equivalent programming measures should be implemented on the PLC side (up
to the $A_OUTSEP variable), i.e. further shutdown conditions can be integrated
to control the output.
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•
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© Siemens AG 2003 All Rights Reserved
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
Note
For this type of control, there is a risk that single-channel actuation of the
brake or the holding brake may not operate correctly in the event of a
PLC fault and that, in the worst case, the axis may fall.
"STOP A/B active"
$VA_DPE[machine axis name] (power enable status – axis-specific)
available in software version 5.x and higher
Alternatively or in addition, system variable $AC_ALARM_STAT
(information about the queued alarm response) (already in
software V4.4.x)
Application-specific SPL signals such as "EMERGENCY STOP not active",
"control system not powered-up", etc.
"STOP A/B active"
SGA "pulses safely cancelled", axis DB.DBX 108.2
Status signal "pulses enabled", axis DB.DBX 93.7
Status signal "speed controller active", axis DB.DBX 61.6
Application-specific SPL signals such as "EMERGENCY STOP not active",
"control system not powered-up", etc.
8 Application examples
8.2 Two-channel brake control with SI (SPL)
Compare
$VA_DPE
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