Keysight 34934A - Page 15

Overview of the 34934A 1
Keysight 34934A User’s Guide 15
Row Protection
For reed relays, user-attached reactive loads and module parasitic capacitance
may result in high in-rush currents. The 34934A module provides a method of
protecting the reed relays from in-rush current, called Row Protection. The
module incorporates sixteen 100Ω resistors, one for each bank of 32 columns
within a row. Each of these resistors is in parallel with a bypass relay, as shown
below.
The row protection mode is set with the command:
SYSTem:MODe:ROW:PROTection <slot>, <mode>
The mode parameters are listed below along with descriptions of the modes. The
selected mode applies to all channels within all matrices of the 34934A module in
the selected slot.
AUTO100 In this mode, closing any channel also closes the Row Protection
Relay for that row, placing a 100Ω resistor in the signal path from that channel’s
32-column bank (see above). The Row Protection Relay remains closed while any
channel in that 32-channel bank is closed. The protection relay opens after all
channels in that bank are opened.
AUTO0 In this mode, closing a channel also closes the Row Protection Relay for
that row, placing the 100Ω protection resistor momentarily in the signal path from
that channel’s 32-column bank to dissipate inrush current. The protection relay is
then opened and shunted by the bypass relay.
FIXed In this mode, all 16 Row Protection Relays are closed, placing the 100Ω
resistors in the signal paths from each 32-column bank. This operation is
Row 1
Col
1
Col
3
Col
2
Col
32
Typical Row Schematic, Illustrating Row Protection Relay and Bypass Relay
Bypass Relay
100Ω
Protection Resistor
Row Protection
Relay