Siemens SINUMERIK 840C Installation Instructions Manual page 374

07.97
NC MD
1824*
Bit 7
Bit 6
Bit 5 Bit 5=1 The function "Set reference dimension" is active.
Bit 4 Bit 4=0 Processing of the determined actual values is continued without changing the
Bit 4 Bit 4=1 The sign of the determined actual values is altered before calculation.
Active:
Bit 3
Bit 2
Bit 1 Bit 1=0 No second measuring system available. The MDs assigned to the second
Bit 1 Bit 1=1 A second measuring system is available. The MDs assigned to the second
If a C axis has two measuring systems, the second measuring system is always that of the
spindle, MD 400*. MD 1388* and MD "2nd MS exists" have no effect with spindle C axis
combinations. Measuring circuit switchover is set such that after a C axis switchover the
spindle encoder is effective until the axis-specific interface signal "Measuring circuit 2 active"
has been evaluated. For C axes with one measuring system, the 1st measuring system must
be the same as that of the spindle.
Bit 0
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SINUMERIK 840C (IA)
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7 6
Effect of LEC on mea-
suring systems 00=first
01=second
10=both
11=both
Assignment of LEC to measuring system 1/2
Bit 7=0 LEC acts on one measuring system (select measuring system via bit 6)
Bit 7=1 LEC acts on both measuring systems
Assignment of LEC to measuring system 1/2 (no effect if Bit 7 = 1)
Bit 6=0 LEC acts on first measuring system
Bit 6=1 LEC acts on second measuring system
sign.
Identifies that the sign of the actual values determined for the second
measuring system must be reversed. When setting, please make sure that the
control direction in the position control loop is correct.
Immediately
Applies to feed axes only.
With bit 3 the user can decide whether with "Set reference dimension" only
the signal "Reference point reached" is set or whether the absolute system is
also set to the value defined by MD 240*. Bit 3 is only active with the function
"Set reference point" and does not affect normal reference point approach.
Digital drives only:
Bit 2=0 No multiple assignment of setpoints permitted (Power On monitoring)
Bit 2=1 Multiple assignment of setpoints is permitted (on-line monitoring when access
priority problems)
measuring system are not active. The MD bit only applies to feed axes. If a
spindle/C axis is in use, MD 200* and 400* are compared to determine whether
a second measuring system has been defined.
measuring system are active. It is possible to switch between the two
measuring systems using the interface signal "Measuring system 1/2".
Active: After POWER ON
This bit must be set to 1 if quadrant error compensation is also to be active for
very small axis accelerations on the first recognized zero crossover. In this
case the compensation also affects a position change in very short positioning
operations.
ManualsBase.com
6 NC Machine Data (NC MD), NC Setting Data (NC SD)
Bit No.
5 4 3
Set abso-
Sign
Setting of
lute system
change
reference
to reference
actual value
dimension dimension
2 (as from
(as from
allowed
SW 2)
SW 3)
6FC5197- AA50
6.7.1 Axis-specific MD bits 2 (axial bits 2)
2 1
2nd
Multiple QEC
measuring
assign. set- undelayed
system
points (as (as from
exists (as
from SW 3) SW 5)
from SW 2)
0
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