Siemens SINUMERIK 840C - Manual (Page 366)

01.99 6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.7.1 Axis-specific MD bits 2 (axial bits 2)
7 6 5 4 3 2 1 0
Bit No.
NC MD
1804*
Adaptation
(as from
SW 2)
Quadrant
error comp-
ensation (as
from SW 2)
Axis can
travel
against fixed
stop (as from
SW 3)
Sensor
signal PLC
fixed stop
(as from
SW 3)
Monitoring
clamping
tolerance
act. (as from
SW 3)
Automatic
tacho comp-
ensation (as
from SW 2)
Symmetrical
traversing
range
ENDAT
absolute
encoder (as
from SW 6)
Standard value: 0000 0000
Bit 7 See Section entitled ”Functional Descriptions”
Bit 6 See Section entitled ”Functional Descriptions”
Bit 5 Bit 5=0 Axis cannot move against fixed stop.
Bit 5=1 Axis can move against fixed stop.
This bit must be set for any axis which is allowed to move against the fixed
stop.
Caution:
MD 1804*, bit 5, must only be set for real axes. It must not be set for fictitious
main and coupled-motion axes.
Bit 4 Bit 4=1 "Fixed stop reached" is sent to the NC via an external sensor.
Bit 4 Bit 4=0 "Fixed stop reached" is calculated internally by the servo from the following
error increase factor.
Bit 3 Bit 3=0 Zero speed monitoring for moving against fixed stop off
Bit 3=1 Zero speed monitoring for moving against fixed stop on
Bit 1 The function ”Tacho compensation” is used to compensate for drive and
tacho characteristic errors which can occur with an analog coupling (e.g.
temperature problems). The function can also be used to correct incorrect
tacho settings. Deviations of up to 12.5 % of the multgain (setpoint
adaptation/maximum load speed) can be compensated (multgain adjustment).
The tacho compensation calculates a new compensation value if:
• a constant velocity is used for traversing and
• the velocity of the axis is greater than 6.25 % of the maximum velocity.
If one of these conditions is not fulfilled, the compensation value remains
constant at the last calculated value. If the compensation value exceeds 12.5
% of the set multgain, this limiting value is used for the compensation.
A separate compensation value is derived for each traversing direction in order
to be able to compensate for asymmetrical drive and tacho characteristics.
The function compensates for deviations of the real as compared to the
calculated ideal following error. To ensure following error-free movement, the
speed feed-forward control must be used with 100 % feedforward control
factor.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 6–181
SINUMERIK 840C (IA)