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Keysight 34931A-34933A User’s Guide
34933A Dual/Quad 4x8 Reed Matrix
Using program commands or the front panel of the 34980A, you can configure the
34933A dual/quad 4x8 reed matrix module for differential (2-wire) mode or
single-ended (1-wire) mode.
The 34933A module contains 100
Ω
in-rush resistors that are used to protect the
reed relays from reactive loads. If you have applications where in-rush resistors
interfere with measurements, connections are provided on the terminal blocks for
you to bypass the in-rush resistors that are located on the columns. See the
simplified schematics on
. However, if you choose to bypass
the in-rush resistors, the life of the reed relays that you bypass may be degraded.
Two-Wire Mode
To physically configure the module for 2-wire mode, use the 34933T-001 terminal
block, or a compatible standard or custom cable. If using a standard or custom
cable, make sure you connect interlock pins 17 and 33 on the Matrix 2 D-sub
connector. Refer to the pinout drawing and table on
.
In 2-wire mode, the 34933A module contains two matrices, each with 32 2-wire
crosspoint non-latching reed relays organized in a 4-row by 8-column
configuration. Every row and column are made up of two wires each, a high (H)
and a low (L). Each crosspoint relay has a unique channel number representing
the row and column that intersect to create the crosspoint. For example, channel
308 represents the crosspoint connection between row 3 and column 08 (all
columns consisting of two digits; in this case the digits are 08). See the simplified
schematic on
You can connect any combination of inputs and outputs at the same time.
However, only Matrix 2 in 2-wire mode of this module connects to the Analog
Buses. By closing channels 921 and 922 you can connect rows 5 and 6
respectively to the internal DMM of the 34980A mainframe for voltage and
resistance measurements.
In 2-wire mode, you can close no more than 20 channels simultaneously due to
power dissipation. However, note that Analog Bus relays count half as much as
channel relays in that total. For example, with one Analog Bus relay closed, you
can close up to a maximum of 19 channel relays. If you try to close more than the
allowed number of channels, you will receive an error message.
