Local Bus Daisychaining; Figure 2-5, 1260 Series Master And Slave Lbus Interconnections - Racal Instruments 1260 Series User Manual

Local Bus
Daisychaining

Figure 2-5, 1260 Series Master and Slave LBUS Interconnections

Installation Instructions 2-6
All modules slaved to a master must be daisychained together
along the VXI Local bus to allow communication between the
Master and its Slaves. The modules must also be isolated from the
rest of the VXI modules on the local bus. The daisychaining of the
Master and Slaves is implemented by the LBus Jumper PCBA
(Racal Instruments P/N 405951) fitted to connector J4 on the
modules and closing the S2 and S3 switches fitted to the
underside of the module. The jumper board connects the local bus
to the module from the left, and the switches connect the module
to the local bus on the right of the module. The module fitted to the
rightmost slot used must have all switches open to isolate the 1260
group from the rest of the VXI modules using the local bus. Note
the 1260-40 has jumpers in positions E126 - E136 instead of DIP
switches. Refer to Figure 2-5 which shows the LBus daisychaining
required by a 1260 Master and Slaves.
If you are using more than eight 1260 series modules, you must
add a termination jumper to the module on the far right. Do this by
soldering a short wire jumper across W22 on the LBUS jumper
PCBA (P/N 401951, Rev. E).
Similarly, a provision must be made to pass the IACK and
BUSGRANT 0-3 signals through Slave modules. This is done by
installing the BUSGRANT Bypass PCBA (Racal Instruments P/N
401951-003) onto the modules' J3 connector. This PCBA is not
required if the VXI chassis backplane contains jumpers or switches
to bypass these signals and the switches are CLOSED
1260 Series User Manual
Revised 11/19/01