System Diagnostics - Keysight Technologies 34945A Configuration Manual

11 | Keysight | 34945A, L4445A, and L4490A/L4491A - Configuration Guide
System Interconnections
Defined
The following sections describe the
interconnections and components of the
34945A, L4445A, and L4490A/L4491A as
shown in Figures 2 and 3.
PC to 34945A, L4445A, or
L4490A/L4491A
When connecting the PC directly to the
34980A (34945A), L4445A, or L4490A/
L4491A, the LAN cross-over cable (p/n
5061-0701) provided with the instruments
is used. If your PC supports Auto-MDIX
or contains a LAN card with Gigabit data
transfer rates, the cross-over cable is not
required. A standard LAN cable may be
used instead. For network configurations
that include a LAN switch or router
between the PC and the instruments,
standard LAN cables are used.
Connections from the PC to the 34980A
(34945A) are also available through the
34980A GPIB and USB ports. Connection
via the optional GPIB interface is also
available for the L4445A and L4490A/
L4491A. However, access to the instru-
ment Web interfaces is only available
through the LAN connection (see the
product user's guide).
34945A, L4445A, or
L4490A/L4491A to 34945EXT
As described in Step 2, Microwave
switches/attenuators are connected to the
34945A, L4445A, and L4490A/L4491A
through distribution boards (Y1150A
– Y1155A) installed on the 34945EXT
module. The 34945EXT is divided into four
banks (1–4) organized by channel number.
Any distribution board may be installed in
any bank, and multiple distribution boards
of the same type may be installed on the
same 34945EXT module.
Each 34945A or L4445A configuration
must contain at least one 34945EXT
module (a "master") with limits on the
configuration as follows:
– Up to eight 34945EXT modules
allowed per 34980A mainframe which
can consist of eight 34945A modules
each with one 34945EXT module,
a single 34945A module with up to
eight 34945EXT modules, or any
combination in between,
– Up to eight 34945EXT modules
allowed per L4445A.
The 34945A and L4445A are connected
to the master 34945EXT using the 9-pin
D-Sub extension cable (8121-1289)
through which +24 V is also supplied.
A (master) 34945EXT module is built into
the L4490A and L4491A chassis. Up to
seven 34945EXT modules (in addition to
the master) are allowed per L4490A and
L4491A. A second 34945EXT module
(the first slave) is available in the L4491A
chassis as Option 002.
34945EXT to 34945EXT
Multiple (slave) 34945EXT modules are
connected through the expansion bus
ports using standard (i.e. non cross-over)
LAN cables. A LAN cable (p/n 8121-1339)
is included with each 34945EXT for this
purpose. The master EXT module must be
connected to the first slave module via the
(master's) Expansion Bus Port 1, and either
Port 1 or Port 2 of the slave EXT module.
The expansion ports on the slave modules
are interchangeable.
34945EXT to external
power supplies
All slave 34945EXT modules and those
external to the L4490A or L4491A chassis
must use an external power supply or
supplies. The 34945EXT can only support
one external voltage level (+24 V, +12V, +5
V) at a time which applies to all distribu-
tion board banks on the 34945EXT. An
external supply can also be used with the
master 34945EXT.
Numbering schemes
The channel numbers associated with
each bank on the 34945EXT are shown in
the following chart. The channel syntax
for the 34980A (34945A), L4445A, and
L4490A/L4491A is also shown.
Bank Channels Channels
(lower) (upper)
Bank 1 01 – 08 11 – 18
Bank 2 21 – 28 31 – 38
Bank 3 41 – 48 51 – 58
Bank 4 61 – 68 71 – 78
– 34945A
<slot #> <ext #> <ch #>
- slot #: 1-8 (34980A)
- ext # : 1-8 (34945EXT)
- ch #: see chart
– L4445A
<1> <ext #> <ch #>
- ext # : 1-8 (34945EXT)
- ch #: see chart
– L4490A/L4491A
<1> <ext #> <ch #>
- ext # : 1-8 (34945EXT)
- ch #: see chart
34945EXT modules are numbered ac-
cording to their position in the daisy-chain
sequence relative to the master 34945EXT
which is ext # 1.

System diagnostics

Often the most common problems with
switches/attenuators connected to the
34945EXT through distribution boards
are related to the switch and attenuator
cables. A seventh distribution board, the
Y1156A Verification Board, is used to
provide visual confirmation of the signal
path from the PC to distribution board
banks 1–4. Verifying the path from the PC
to a selected bank helps isolate suspected
problems in the entire path from PC to
switch.
Many Keysight switches contain position
indicator options that allow for electronic
verification of the switch position. The
34945EXT contains circuitry to detect
these signals, and the Y1156A diagnostic
board can also be used to test the
functioning of this circuitry.
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