GE Industrial Solutions 6KCV301DGF - Manual (Page 27)

27 —————— Digital General Function Card ——————
6KCV301DGF
2.1.6.1 DPRAM hardware
From the hardware point of view, the DPRAM is a bi-accessible storage device.
RAM ROM
Microp.
RAM ROM
Microp.
D
P
R
A
M
DGFC_386
Figure 2.1.7.1.1: DPRAM Hardware
As shown above, the drive microprocessor accesses its own RAM and ROM and
DPRAM on the DGF. The DGF microprocessor accesses its own RAM and ROM and
DPRAM. The DPRAM chip is 2 Kbytes RAM storage. The feature of this chip is that
the storage cells can be accessed by the two buses but these buses cannot access each
other. This permits the two cards to exchange data without affecting each other.
2.1.6.2 DPRAM software organization
The DPRAM storage area has been designed with different areas to support the different
types of connection between the DGF and the Drive. These connections satisfy different
needs and are executed at different times and with different modalities. The need to
build up different kinds of connections comes from the need to satisfy and coordinate
the different elements of the system.
The drive parameters can be divided into three categories, according to the speed with
which it is possible to access them:
- “parameters of configuration”: the access time is very long so that it is not possible
to use them in the automatic connections .
- “low priority” parameters: they have a medium access time so that it is possible to
use them through the automatic asynchronous connection .
- “high priority” parameters: they have a quick access time so that it is possible to
use them with all the automatic connections.