34923A 40/80-Channel Reed Multiplexer - Agilent Technologies 34921A User Manual

34923A 40/80-Channel Reed Multiplexer

The 34923A 40/80- Channel Reed Multiplexer (40/80- Ch Reed MUX) is
divided into two equal banks of non- latching reed switches. This module
also contains eight armature Analog Bus relays (channels 911- 914 and
921- 924), four on each bank that can connect the bank relays to the
system Analog Buses. You can connect any of the channels to the internal
DMM through ABus1 and ABus2 for voltage or resistance measurements.
Using program commands or the mainframe front panel, you can control
each of the channel switches individually, and configure this module for
differential (2- wire or 4- wire) or single- ended (1- wire) mode. Refer to the
simplified schematics on
If you are using an Agilent 34923T- 00x terminal block to connect your
DUT to this module, be sure to use the terminal block that corresponds to
your module configuration mode (Refer to the terminal block drawings on
page 23
34923T-001 (Option 001
34923T-002 (Option 002) Terminal block for single-ended (1-wire) mode
You can confirm the mode in which your module is configured by using
the SYSTem:CTYPe? <slot number> program command. This command
returns the identity of the plug- in module in the specified slot.
In all modes, this module has capability to scan as many as 500
channels/second using the internal DMM. With the automatic
"break- before- make" connection operation, you are assured that no two
signals are connected to each other during a scan.
This module is interlock protected, which means whenever the D- sub
connector end of the modules is exposed, the Analog Bus relays
immediately open and disconnect from the Analog Bus. For more
information, see
drawings on
Lifetime of relays is severely degraded as current or voltage goes up.
If higher voltage is being switched, limits on source current are
recommended.
When the power is off, all channel and Analog Bus relays open.
Agilent 34921A-34925A Low Frequency Multiplexer Modules User's Guide
and page 26.):
Terminal block for differential (two- or four-wire) mode
Whenever you change from 2- or 4-wire mode to 1-wire mode, or the
N O T E
reverse, you must cycle power on the 34980A for the configuration
to take effect.
"Safety Interlock"
page 22 and
Because user-attached reactive loads and backplane parasitic
C A U T I O N
capacitance may result in high in-rush currents, 100
resistors protect the reed relays from damage and performance
degradation. Therefore, you must consider these resistors when
you are designing a measurement. Refer to the simplified
schematics on
34923A 40/80-Channel Reed Multiplexer
page 21 and page 24.
on page 3 and the D- Sub connector
page 25.
page 21 and page
Ω
in-rush
24.
19