Siemens SINUMERIK 840C Installation Instructions Manual page 374

07.97
NC MD 7
Effect of LEC on mea-
suring systems 00=first
1824*
01=second
10=both
11=both
Bit 7 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
Bit 6 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
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
sign.
Bit 4 Bit 4=1 The sign of the determined actual values is altered before calculation.
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.
Active: Immediately
Applies to feed axes only.
Bit 3 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.
Bit 2 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)
Bit 1 Bit 1=0 No second measuring system available. The MDs assigned to the second
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.
Bit 1 Bit 1=1 A second measuring system is available. The MDs assigned to the second
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
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 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.
©
Siemens AG 1992 All Rights Reserved
SINUMERIK 840C (IA)
6 NC Machine Data (NC MD), NC Setting Data (NC SD)
Bit No.
6 5 4
Sign
Setting of
change
reference
actual value
dimension
2 (as from
allowed
SW 2)
6FC5197- AA50
6.7.1 Axis-specific MD bits 2 (axial bits 2)
3 2 1
Set abso-
2nd
Multiple
lute system
measuring
assign. set-
to reference
system
dimension points (as
exists (as
(as from
from SW 3)
from SW 2)
SW 3)
0
QEC
undelayed
(as from
SW 5)
6–189