National Instruments 800 Series 用户手册

下载
页码 104
Appendix E
Modifying and Installing I/O Expansion Boards
© National Instruments Corporation
E-5
Length of VXIpc-860 Plug-In Boards
The VXIpc-860 can accommodate PCI or ISA I/O boards that are up to 
4.2 in. high and up to 8.4 in. long. When DRAM SIMMs 0.85 in. are 
used on the processor board, the component-side component height on 
a PCI I/O board shall be 0.48 in. tall in the area shown in Figure E-4. 
For the same height DRAM SIMMs, the ISA I/O board solder-side 
component height shall be 0.07 in. tall in the area shown in Figure E-4. 
Be sure to allow for clearance if you want to use taller DRAM SIMMs.
Because DRAM SIMMs taller than 0.85 in. are more likely to interfere 
with ISA cards than PCI cards, the two are discussed separately in the 
following sections.
Length of PCI Plug-In Boards
The VXIpc-860 accommodates any 32-bit, 5 V PCI I/O boards that are 
a maximum of 8.4 in. long with the standard height of 4.2 in. (see 
Figure E-5). PCI cards are installed in the VXIpc-860 such that the 
board components face the processor board, which contains the 
processor and system RAM. PCI components (higher than 0.48 in. in 
the area shown in Figure E-4) on a plug-in board may physically contact 
the DRAM SIMMs installed on the CPU card, as shown in Figure E-5. 
Figure E-5.  Length Restrictions for PCI Plug-In Boards Used with the VXIpc-860
Because larger DRAM sizes may employ taller SIMMs, you must be 
careful that the component height of the PCI board does not interfere 
with the SIMMs in such a way that electrical shorts occur or that the PCI 
board is stressed enough to compromise its physical or electrical 
integrity.
PCI Card
Heat Sink
Riser Card
Front Panel
Possible Support
Bracket Positions
.85 in. High
SIMMs
.48 in.
VXI Connector
8.4 in. max