6 Assi
nin
Parameters to the Control and the PLC Pro
ram
6
03.96
6.6 System data
6-99
Siemens AG 2000 All Rights Reserved
SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
6.6 System data
6.6.1 Basic settings
The control operates according to time cycles which are defined via machine
data. The basic system clock cycle is defined in seconds; the other time cycles
are calculated through multiplication with the basic system clock cycle.
The time cycles are set as standard to an optimum and should only be changed
if the requirements of the NC cannot be fulfilled with the preset values.
Table 6-5 Control time cycles
Machine data Name NCU 571 NCU 572 NCU 573
MD 10050: SYSCLOCK_CYCLE_TIME Basic system
clock cycle
= 0.0060 s ––>
6 ms
= 0.0040 s ––>
4 ms
= 0.0020 s ––>
2 ms
MD 10060:
POSCTRL_SYSCLOCK_TIME_RATIO
Factor for
position control
clock cycle
= 1 = 1 ∗ 6 ms
= 6 ms
= 1 = 1 ∗ 4 ms
= 4 ms
= 1 = 1 ∗ 2 ms
= 2 ms
MD 10070: IPO_SYSCLOCK_TIME_RATIO Factor for
interpolator clock
cycle
= 4 = 4 * 6 ms
=24 ms
= 4 = 4 * 4 ms
=16 ms
= 4 = 4 * 2 ms
=8 ms
!
Warning
If you have changed the time cycles, check that the operating response of the
control is correct in all operating modes before ending the start-up process.
A control system is switched over from the metric to an inch system by means
of MD 10240: SCALING_SYSTEM_IS_METRIC (basic system metric, active
after power ON). The additional conversion factor is specified in MD 10250:
SCALING_VALUE_INCH (conversion factor for switchover to INCH system,
factor = 25.4). The existing data are converted to inches after power ON and
displayed. After switchover data must be entered in inches.
Setting MD 10260: CONVERT_SCALING_SYSTEM=1 in SW version 5 has
made it considerably easier to switch the dimension system over.
S Availability of an MMC softkey in the “MACHINE” operating area for dimen-
sion system switchover.
S Automatic conversion of NC active data when dimension system
is switched over.
S Data back-up with current dimension system identifier.
S Machine data MD 10240: SCALING_SYSTEM_IS_METRIC becomes active
on Reset.
S The dimension system for sag compensation is configured in
MD 32711:CEC_SCALING_SYSTEM_METRIC.
The basic programming setting (G70, G71, G700, G710) is switched over on a
channel-specific basis in MD 20150: GCODE_RESET_VALUES [12]. In the
case of softkey toggling via MMC, the value changes between G700 (inches)
and G710 (metric).
In SW version 5 and later, feedrates (inch/min or mm/min) are interpreted in the
dimension system in addition to length data in response to G700/G710.
Control time
cycles
Switchover from
metric to inch
system
12.9812.98
To Next Page
Loading...
Need help?
General
