Siemens SINUMERIK 840C Installation Instructions Manual page 1041

12 Functional Descriptions
12.25.4 Memory configuration on control power-up
• If a module with 486 CPU is installed and digital drives are connected, the MD mentioned
above must be set to "1".
Loading the drive software as from SW 6
General notes:
Up to SW 5 the drive software (MSD and FDD) is loaded from the MMC hard disk into the
NCK user memory in its entirety while the control powers up and is then transferred to the
drive when the drive powers up. For this, the use must make 192 Kbytes of NCK memory
available per package.
As from SW 6 this memory is not large enough for the drive software. There are two ways of
loading the drive software.
1. Increase the size of the NCK user memory for MSD/FDD
Advantage: Fast loading of the drive software
Disadvantage: Larger user memory requirement
2. Retroload the drive software from the hard disk in packages
Advantage: No additional user memory requirement
Disadvantage: Longer power-up times
The available memory is set via NC-MD 60016. The drive software memory requirement can
be increased from 288 Kbytes to 384 Kbytes for more recent software versions. If less
memory is made available than is needed for the drive software, the missing software is
retroloaded from the hard disk, thus increasing the time which the control takes to power up.
Number of drive
No.
packages
1 1 (MSD or FDD)
2 1 (MSD or FDD)
3 2 (MSD or FDD)
4 2 (MSD or FDD)
5 2 (MSD or FDD)
Lines 1 and 4 give settings that are compatible with 840C SW 3 and 5. They result in a (slight)
increase in the power-up time without requiring more user memory.
Lines 2 and 5 show the recommended settings for 840C SW 6. Here, more user memory is
required but power-up is quickest with these settings.
Line 3 shows a setting that requires less user memory than SW 3-5. However, here the power-
up time of the control has increased considerably.
12–266
Corr. to
Memory required
MD 60014
192 K
288 K
192 K
384 K
576 K
© Siemens AG 1992 All Rights Reserved
Power-up time
increased
2 yes
3 no
2 yes, considerably
4 yes
6 no
6FC5197- AA50
SINUMERIK 840C (IA)
07.97