Siemens Sinumerik 840D sl Function Manual page 94

Basics on the safety functions integrated in the system/drive
5.4 Actual value conditioning
Drive parameters
r0469 Resolution measurement steps for linear
absolute encoders (linear DRIVE--CLiQ
encoders)
r0470 Valid bits for the redundant coarse position
value (DRIVE--CLiQ encoder, binary)
r0471 Fine resolution of the redundant coarse po-
sition value (DRIVE--CLiQ encoder, binary)
r0472 Relevant bits of the redundant coarse posi-
tion value (DRIVE--CLiQ encoder, binary)
r0473 Non safety--related measurement steps
position value POS2 (DRIVE--CLiQ enco-
der, linear)
r0474 Configuration of the redundant coarse posi-
tion value
Bit 0: Count direction, up/down
Bit 1: CRC 16: LSB/MSB first
Bit 2: MSB/LSB -- justified
Bit 4: Binary comparison not possible
r0475 = Safety MSB of the redundant coarse posi-
r0470 -- r0471 tion value (DRIVE--CLiQ encoder, binary)
The difference between DRIVE--CLiQ encoder, binary or linear, is derived from
drive parameter r0474, bit 4:
S r0474.4 = 0: DRIVE--CLiQ encoder, binary
S r0474.4 = 1: DRIVE--CLiQ encoder, linear or not binary
The relevant drive parameters are evaluated, depending on the DRIVE--CLiQ pro-
totype (binary or linear). Different algorithms are used to compare the redundant
coarse position value with the actual value. All of the NCK machine data listed in
the table above are incorporated in the checksum via the axis--specific NCK
machine data in order to identify any inadvertent changes.
Machine data
S $MA_SAFE_ENC_NUM_BITS[0,1]
S $MA_SAFE_ENC_CONF
are incorporated in the hardware--related checksum check
$MA_SAFE_ACT_CHECKSUM[1]. If one of these NCK machine data do not
match the associated drive parameter, then Alarm 27035 "Axis %1 new HW com-
ponent, acknowledgment and function test required" is output.
The following machine data
S $MA_SAFE_ENC_NUM_BITS[2,3]
S $MA_SAFE_ENC_MEAS_STEPS_RESOL
S $MA_SAFE_ENC_MEAS_STEPS_POS1
have a direct impact on the accuracy of the safe position monitoring, and are
therefore factored into the functional checksum scope $MA_SAFE_ACT_CHECK-
5-94
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
Meaning NCK machine data
$MA_SAFE_ENC_MEAS_STEPS
_RESOL
$MA_SAFE_ENC_NUM_BITS[0]
$MA_SAFE_ENC_NUM_BITS[1]
$MA_SAFE_ENC_NUM_BITS[2]
$MA_SAFE_ENC_MEAS_STEPS
_POS1
$MA_SAFE_ENC_CONF
$MA_SAFE_ENC_NUM_BITS[3]
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